Class 10

AP State Board Syllabus AP SSC 10th Class Physics Solutions Chapter 5 Refraction of Light at Plane Surfaces Textbook Questions and Answers.

AP State Syllabus SSC 10th Class Physics Solutions 5th Lesson Refraction of Light at Plane Surfaces

10th Class Physics 5th Lesson Refraction of Light at Plane Surfaces Textbook Questions and Answers

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Question 1.
Why is it difficult to shoot a fish swimming in water? (AS1)
(OR)
If the fish is swimming in water, why it is difficult to shoot?
(OR)
A shooter finds it difficult to shoot a fish swimming in water. Why?
Answer:
Due to refraction of light, it is difficult to shoot a fish swimming in water.

Reason :
The light rays coming from the fish towards shooter, bend at water-air interface. So, shooter sees only image of the fish, but not actual fish.

Question 2.
The speed of light in a diamond is 1,24,000 km/s. Find the refractive index of diamond if the speed of light in air is 3,00,000 km/s. (AS1)
Answer:
Speed of light in diamond = 1,24,000 km/s
Speed of light in vacuum = 3,00,000 km/s

Question 3.
Refractive index of glass relative to water is 9/8. What is the refractive index of water relative to glass? (AS1)
Answer:
Refractive index of glass relative to water = \(\frac{n_{g}}{n_{w}}=\frac{9}{8}\)
∴ Refractive index of water relative to glass = \(\frac{\mathrm{n}_{\mathrm{w}}}{\mathrm{n}_{\mathrm{g}}}=\frac{8}{9} \cdot\left[\because \mathrm{n}_{12}=\frac{1}{\mathrm{n}_{21}}\right]\)

Question 4.
The absolute refractive index of water is 4/3. What is the critical angle ? (AS1)
Answer:
Absolute refractive index of water = 4/3

Critical angle of water = C = 48°5′ = 48.5°.

Question 5.
Determine the refractive index of benzene if the critical angle is 42°. (AS1)
Answer:
Critical angle of benzene = 42°.

Question 6.
Explain the formation of mirage. (AS1)
(OR)
How is the mirage formed? Explain.
(OR)
A person walking on a road observed some water being present on the road but when he went there actually he did not find water. What is that actually formed called? Explain that process.
(OR)
Sometimes during the hot summer at noon time on tar roads, it appears that there is water on the road, but there would really be no water. What do you call this phenomenon? Explain why it happens.
(OR)
Why do you see a mirage the road on a hot summer day?
Answer:

• During hot summer day, air just above the road surface is very hot and the air at higher altitudes is cool.
• We know that refractive index of air increases with density.
• So, the cooler air at the top has greater refractive index than hotter air just above the road.

• Light travels faster through the thinner hot air than the denser cool air above it.
• On hot days, the temperature decreases with height.
• Thus the refractive index of air increases with height.
• When the light from a tall object such as tree or from the sky passes, through a medium just above the road whose refractive index decreases towards ground, suffers refraction and takes a curved path because of total internal reflection.
• This refracted light reaches the observer in a direction shown as in second figure.
• This appears to the observer that the ray is reflected from ground.
• Hence we will see water on road, which is the virtual image of sky and an inverted image of tree on the road.
• Such virtual images of distant high objects cause the optical illusion called ‘mirage’.

Question 7.
How do you verify experimentally that \(\frac{\sin i}{\sin r}\) is a constant? (AS1)
(OR)
Explain the experiment that shows the relation between angle of incidence and angle of refraction through figure.
(OR)
Write an experiment to obtain the relation between angle of incidence and angle of refraction.
Answer:
Aim:
Identifying relation between angle of incidence and angle of refraction.

Materials required :
A plank, white chart, protractor, scale, small black painted plank, a semi-circular glass disc of thickness nearly 2 cm pencil and laser light.

Procedure :

1. Take a wooden plank which is covered with white chart.
2. Draw two perpendicular lines, passing through the middle of the paper as shown in the figure (a).
3. Let the intersecting point be O.
4. Mark one line as NN which is normal to the another line marked as MM.
5. Here MM represents the line drawn along the interface of two media and NN represents the normal drawn to this line at ‘O’.
6. Take a protractor and place it along NN in such a way that its centre coincides with ‘O’ as shown in figure (b).
7. Then mark the angles from 0° to 90° on both sides of the line NN.
8. Repeat the same on the other side of the line NN.
9. The angles should be represented on circular line.
10. Now place semi circular glass disc so that its diameter coincides with the interface line (MM) and its centre coincides with the point O.
11. Take the laser light and send it along NN in such a way that the laser propagates from air to glass through the interface at point O and observe the way of laser light coming from other side of disc.
12. There is no deviation.
13. Send Laser light along a line which makes 15° (angle of incidence) with NN and see that it must pass through point O.
14. Measure its corresponding angle of refraction.
15. Repeat the experiment with angle of incidences of 20°, 30°, 40°, 50° and 60° and note the corresponding angles of refraction.

Observation :

• Find sin i, sin r for every i and r note down the values in table.

• Evaluate \(\frac{\sin i}{\sin r}\) for every incident angle i.
• We get \(\frac{\sin i}{\sin r}\) as constant.
• That is the relationship between angle of incidence and angle of refraction.
• The ratio of sin i and sin r is called refractive index.

Question 8.
Explain the phenomenon of total internal reflection with one or two activities. (AS1)
Answer:
Procedure :

1. Place the semi-circular glass disc in such a way that its diameter coincides with interlace line MM and its center coincides with point O’.
2. Now send light from the curved side of the semicircular glass disc.
3. The light travels from denser medium to rarer medium.
4. Start with angle of incidence (i), equals to 0° and observe for refracted on other side of the disc.
5. It does not deviate into its path when entering rarer medium.
6. Send laser light along angles of incidence 5°, 10°, 15°, etc. and measure the angle of refraction.
7. And tabulate the results in the given table.

Observation :

• Make a table shown below and note the values ‘i’ and ‘r’.

• At particular angle of incidence, the refracted ray does not come out but grazes the interface separating the air and glass. This angle is called critical angle.
• When the angle of incidence is greater than critical angle, the light ray gets reflected into denser medium at the interface, i.e. light never enters rarer medium. This phenomenon is called total internal reflection.

Question 9.
How do you verify experimentally that the angle of refraction is more than angle of incidence when light rays travel from denser to rarer medium? (AS1)
(OR)
When the light rays travel from denser to rarer medium, how can you explain, the angle of refraction is more than angle of incidence experimentally?
Answer:
Procedure :

• Take a metal disc. Use a protractor and mark angles along its edge as shown in the figure.
• Arrange two straws at the centre of the disc, in such a way that they can be rotated freely about the centre of the disc.
• Adjust one of the straws to make an angle 10°.
• Immerse half of the disc vertically into the water, filled in a transparent vessel. While dipping, verify that the straw at 10° must be inside the water.
• From the top of the vessel, try to view the straw which is inside the water as shown in the figure.
• Then adjust the other straw which is outside of the water until both straws look like they are in a single straight line.
• Then take the disc out of the water and observe the two straws on it. You will find that they are not in a single straight line.
• Measure the angle between the normal and second straw. Note the values in the following table.

• Do the same for various angles and find the corresponding angles of refraction and note them in the table.

Observation :
We will find the angle of refraction is more than angle of incidence.
i. e., r > i.

Conclusion :
When light travels from denser (water) to rarer (air) it bends away from the normal.

Question 10.
Take a bright metal ball and make it black with soot in a candle flame. Immerse it in water. How does it appear and why? (Make hypothesis and do the above experiment) (AS2)
Answer:

• The black metallic .ball appears to be raised up in the water because the path of the ray changes its direction at the interface, separating the two media, i.e., water and air.
• This path is chosen by light ray so as to minimize time of travel between ball and eye.
• This can be possible only when the speed of light changes at interface of two media.
• In another way the speed of light is different in different media.

Hypothesis :
Speed of light changes when it travels from one medium to another medium.

Question 11.
Take a glass vessel and pour some glycerine into it and then pour water up to the brim. Take a quartz glass rod. Keep it in the vessel. Observe the glass rod from the sides of the glass vessel.
1) What changes do you notice?
2) What could be the reasons for these changes? (AS2)
Answer:

1. We cannot see the glass rod in glycerine but we can see the rod in water.
2. We can also observe an apparent image of glass rod in water.
3. Reasons:
   i) Glycerine has essentially same refractive index as glass.
   ii) So, any light passing through these is bent equally.
   iii) Since both are transparent, it is not possible for our eye to distinguish the boundary by a change in the angle of reflection, and the glass seems to vanish.
   iv) But, the refractive index of glass and water are different.
   v) So the glass rod is visible to our eye in water. .

Question 12.
Do Activity-7 again. How can you find critical angle of water? Explain your steps briefly. (AS3)
Answer:

Procedure:

1. Take a cylindrical transparent vessel.
2. Place a coin at the bottom of the vessel.
3. Now pour water until you get the image of the coin on the water surface.
4. This is due to total internal reflection.

Critical angle of water :

1. Refractive index of water = 1.33
2. The sine of critical angle of water = \(\frac{1}{\text { Refractive index }}\)
3. Sin C = \(\frac{1}{\text { 1.33 }}\) ⇒ sin C = 0.7518.
   ∴ C = 8.7°
4. ∴ The critical angle of water = 48.7°.

Question 13.
Collect the values of refractive index of the following media. (AS4)

Water, coconut oil, flint glass, crown glass, diamond, benzene and hydrogen gas.

Answer:

Medium	Refractive Index
1. Water	1.33
2. Coconut oil	1.445
3. Flint glass	1.65
4. Crown glass	1.52
5. Diamond	2.42
6. Benzene	1.50
7. Hydrogen gas	1.000132

Question 14.
Collect information on working of optical fibres. Prepare a report about various uses of optical fibres in our daily life. (AS4)
(OR)
What do you know about the working of optical fibres and make a report of various uses of optical fibres in our daily life?
(OR)
How are the optical fibres working? What are the various uses of optical fibres in our daily life?
Answer:
1) An optical fibre is very thin fibre made of glass or plastic having radius about a micrometer (10-6 m).
2) A bunch of such thin fibres form a light pipe.

Working :
1. Optical fibre having three parts-namely core (n = 1, 7), clading (n = 1, 6) and shielding.
2. The ray of light AB gets refracted at point ‘B’ into core and incident at ‘C’ with angle of incidence i (i > c).

3. The angle of incidence is greater than the critical angle and hence total internal reflection takes place.
4. The light is thus transmitted along the fibre.
5. The optical fibre is also based on ‘Fermat’s principle.

Uses :

1. Optical fibres are used in ‘endoscopy’ to see the internal organs like throat, stomach, intestines, etc.
2. Optical fibres are used in transmitting communication signals through light pipes.
3. Optical fibres are used in international telephone cables laid under the sea, in large computer networks, etc.
4. In optical fibre about 2000 telephone signals appropriately mixed with light waves may be simultaneously transmitted through a typical optical fibre.

Question 15.
Take a thin thermocol sheet. Cut it in circular discs of different radii like 2 cm, 3 cm, 4 cm, 4.5 cm, 5 cm etc. and mark centers with sketch pen. Now take needles of length nearly 6 cm. Pin a needle to each disc at its centre vertically. Take water in a large opaque tray and place the disc with 2 cm radius in such a way that the needle is inside the water as shown in figure. Now try to view the free end (head) of the needle from surface of the water.

1) Are you able to see the head of the needle?
Now do the same with other discs of different radii. Try to see the head of the needle, each time.
Note : The position of your eye and the position of the disc on water surface should not be changed while repeating the Activity with’other discs.
2) At what maximum radius of disc, were you not able to see the free end of the needle ?
3) Why were you not able to view the head of the nail for certain radii of the discs ?
4) Does this Activity help you to find the critical angle of the medium (water) ?
5) Draw a diagram to show the passage of light ray from the head of the nail in different situations. (AS4)
Answer:

1. Yes, we can see head of the needle.

2. Height of the pin = 6 cm
Radius of the disc = x cm
Critical angle of water = C = 48.7°
Tan C = 48.7°
\(\frac{x}{6}\) = 1.138 ⇒ x = 6.828 cm
So, at radius of 6.8 cm we cannot see the free end of the needle.

3. Because the light rays coming from object undergoing total internal reflection by touching the surface of disc.

4. Yes, we can find critical angle.
Refractive index of air (n₂) = 1.003 ; Refractive index of water (n₁) = 1.33
Sin C = \(\frac{n_{2}}{n_{1}}=\frac{1.003}{1.33}\) = 0.7541 ⇒ C = 48.7°

5.

Question 16.
Explain the refraction of light through the glass slab with a neat ray diagram. (AS5)
(OR)
Draw a glass slab diagram and explain the refraction of light through glass slab.
(OR)
Write the procedure of a lab Activity to understand lateral shift of light rays through a glass slab.
(OR)
How can you find lateral shift using glass slab?
Answer:
Aim :
A) Determination of position and nature of image formed by a glass slab.
B) Understanding lateral and vertical shift.
C) Determination of refractive index of given glass slab.

Materials required :
Plank, chart paper, clamps, scale, pencil, thin glass slab and pins.

Procedure :

1. Place a piece of chart on a plank. Clamp it. Place a glass slab in the middle of the paper.
2. Draw border line along the edges of the slab by using a pencil. Remove it. You will get a figure of a rectangle.
3. Name the vertices of the rectangle as A, B, C and D.
4. Draw a perpendicular at a point on the longer sides (AB) of the rectangle.
5. Now draw a line, from the point of intersection where side AB of rectangle and perpendicular meet, in such a way that it makes 30° angle with the normal.
6. This line represents the incident ray falling on the slab and the angle it makes with normal represents angle of incidence.
7. Now place the slab on the paper in such a way that it fits in the rectangle drawn. Fix two identical pins on the line making 30° angle with normal, such that they stand vertically with same height.
8. By looking at the two pins from the other side of the slab, fix two pins in such a way that all pins appear to be along a straight line.
9. Remove the slab and take out pins. Draw a straight line by joining the dots formed by the pins up to the edge CD of the rectangle.
10. This line represents emergent ray of the light.
11. Draw a perpendicular to the line CD where our last line drawn meets the line CD.
12. Measure the angle between emergent ray and normal.
13. This is called angle of emergence.
14. The angle of incidence and angle of emergence are equal.
15. Incident emergent rays are parallel.
16. The distance between the parallel rays is called shift.

Question 17.
Place an object on the table. Look at the object through the transparent glass slab. You will observe that it will appear closer to you. Draw a ray diagram to show the passage of light ray in this situation. (AS5)
Answer:

Question 18.
What is the reason behind the shining of diamond and how do you appreciate it? (AS6)
(OR)
For which reason is the diamond shining and how is it appreciable?
Answer:

• The critical angle of diamonds is very low, i.e., 24.4°.
• So if a light ray enters diamond, it undergoes total internal reflection.
• It makes the diamond shine brilliant.
• So total internal reflection is main cause of brilliance of diamonds.
• Majority of people are attracted towards diamonds due to this property.
• So we have to thoroughly appreciate total internal reflection for brilliance of diamonds.

Question 19.
How do you appreciate the role of Fermat’s principle in drawing ray diagrams? (AS6)
(OR)
How do you admire the role of Fermat’s principle in drawing ray diagrams? Fermat’s principle: The light ray always travels in a path which needs shortest possible time to cover distance between two points.
This principle has lot of importance on optics. This is used in

1. Laws of reflection (i.e., angle of incidence = angle of reflection)
2. Laws of refraction (Snell’s law)
3. To derive refractive index of a medium.
4. To derive refractive index of glass slab.
   So, I appreciate the Fermat’s principle.

Question 20.
A light ray is incident on air-liquid interface at 45° and is refracted at 30°. What is the refractive index of the liquid? For what angle of incidence will the angle between reflected ray and refracted ray be 90°? (AS7)
Answer:
i) Given that angle of incidence (i) = 4S°
angle of refraction (r) = 30°

ii) Given that angle between reflected and refracted ray is 90°.
We know angle of incidence = angle of reflection
∴ Angle of refraction (r) = 90 – angle of incidence
= 90 – i

Critical angle = 54.7°. This angle is also known as polarising angle.

Question 21.
Explain why a test tube immersed at a certain angle in a tumbler of water appears to have a mirror surface from a certain viewing position. (AS7)
Answer:
When a test tube is immersed at a certain angle in a tumbler of water appears to have
a mirror surface from a certain viewing positions due to total internal reflection.

Explanation :

• The critical angle for glass is 42°.
• The glass and air in test tube works as denser and rarer mediums.
• The rays of light while travelling through water strike glass – air interface of test tube at an angle of more than 42° (i > c) they get totally internal reflected as shown figure.
• When these reflected rays reach the eye, they appear to come from the surface of test tube itself.
• Now the test tube appears like silvary.

Question 23.
In what cases does a light ray not deviate at the interface of two media? (AS7)
Answer:

1. When a light ray incident is perpendicular to the interface of surface, it does not undergo deviation.
2. When a light ray incident is more than critical angle, it does not undergo deviation (refraction) but it undergoes reflection to come back into the original medium.

Question 25.
When we sit at camp fire, objects beyond the fire seen swaying. Give the reason for it. (AS7)
(OR)
What are the reasons for the objects beyond the fire seen swaying, when we sit at camp fire?
Answer:

• The temperature of the surrounding air changes due to convection of heat by the camp fire.
• This leads to chang in density and refractive index of air, continuously.
• The continuous change in refractive index of air changes the refracted path of the light ray.
• This is the cause for swaying of an object.

Question 26.
Why do stars appear twinkling? (AS7)
(OR)
What is the reason for the appearance of stars like twinkling?
Answer:

• The twinkling of a star is due to atmospheric refraction of star light.
• The atmosphere consists of a number of layers of varying densities.
• When light rays coming from a star pass through this layers and undergo refraction for several times.
• Thats why stars appear twinkling.

Question 27.
Why does a diamond shine more than a glass piece cut to the same shape? (AS7)
(OR)
What is the reason for shining of diamond brightly as compared to glass piece cut?
Answer:

• The critical angle of a diamond is very low (i.e., 24.4°).
• So if a light ray enters a diamond it definitely undergoes total internal reflection.
• Whereas it is not possible with glass piece cut to the same shape.
• So diamond shines more than a glass piece.

Fill In The Blanks

1. At critical angle of incidence, the angle of refraction is ……………… .
2. n₁ sin i = n₂ sin r, is called ……………… .
3. Speed of light in vacuum is ……………… .
4. Total internal reflection takes place when a light ray propagates from …………. to …………… medium.
5. The refractive index of a transparent material is 3/2. The speed of the light in that medium is …………… .
6. Mirage is an example of ……………… .
Answer:

1. 90°
2. Snell’s law
3. 3 × 10⁸ m/s
4. denser, rarer
5. 2 × 10⁸ m/s
6. optical illusion / total internal reflection

Multiple Choice Questions

1. Which of the following is Snell’s law?

Answer:
B)

2. The refractive index of glass with respect to air is 2. Then the critical angle of glass air interface is ………………….
A) 0°
B) 45°
C) 30°
D) 60°
Answer:
C) 30°

3. Total internal reflection takes place when the light ray travels from …………….. .
A) rarer to denser medium
B) rarer to rarer medium
C) denser to rarer medium
D) denser to denser medium
Answer:
C) denser to rarer medium

4. The angle of deviation produced by the glass slab is …………… .
A) 0°
B) 20°
C) 90°
D) depends on the angle formed by the light ray and normal to the slab
Answer:
D) depends on the angle formed by the light ray and normal to the slab

10th Class Physics 5th Lesson Refraction of Light at Plane Surfaces Additional Questions and Answers

Question 1.
Derive Snell’s law.
(OR)
Prove n₁ sin i = n₂ sin r.
(OR)
Derive the Snell’s formula from Fermat’s principle.
(OR)
Derive the formula in realtion with and of incidence and angle of refraction.
Answer:
Let X be the path and A be the point above X and B be the point below X.
Now, we have to find the way from A to B.

1. Let us try to calculate how long it would take to go from A to B by the two paths through point D and another through point C.
2. If we draw a perpendicular DE, between two paths at D, we see that the path on line is shortened by the amount EC.
3. On the other hand, in the water, by drawing corresponding perpendicular CF we find that we have to go to the extra distance DF in water. These times must be equal since we assumed there was no change in time between two paths.
4. Let the time taken by the man to travel from E to C and D to F be ∆t and v₁ and v₂ be the speeds of the running and swimming. From figure we get,
   EC = v₁ ∆t and DF = v₂ ∆t
   ⇒ \(\frac{\mathrm{EC}}{\mathrm{DF}}=\frac{\mathrm{v}_{1}}{\mathrm{v}_{2}}\) ………….. (1)
5. Let i and r be the angles measured between the path ACB and normal NN, perpendicular to shore line X.

10th Class Physics 5th Lesson Refraction of Light at Plane Surfaces InText Questions and Answers

10th Class Physics Textbook Page No. 56

Question 1.
Why should you see a mirage as a flowing water?
Answer:

• A mirage is a naturally occuring optical phenomenon, in which light rays are bent to produce a displaced image of distant objects or the sky.
• As light passes from colder air (higher place) to warmer air (lower place), the light ray bends away from the direction of the temperature gradient.
• Once the rays reach the viewer’s eye, the visual cortex interprets it as if it traces back along a perfectly straight “line of sight”. However this line is at a tangent to the path the ray takes at the point it reaches the eye.
• The result is that an “inferior image ” of the sky above appears on the ground.
• The viewer may incorrectly interprets this sight as water that is reflecting the sky, which is to the brain, a more reasonable and common occurrence.

Question 2.
Can you take a photo of a mirage?
Answer:

• Yes, I can take a photo of a mirage.
• Our eye can catches the total internal reflected rays.
• So, camera lens also catches the same.

10th Class Physics Textbook Page No. 46

Question 3.
What difference do you notice in fig 2(a) and Fig 2(b) with the respect to refracted rays?
(OR)
Draw the ray diagram of refraction in between denser and rarer medium.

Answer:
In figure 2(a) the light ray bends towards normal whereas in 2(b) the light ray bends away from the normal.

Question 4.
Is there any relation between behaviour of refracted rays and speed of the light?
Answer:
Yes. The speed of light changes when it travels from one medium to another medium. So the light may bend towards normal or away from normal.

10th Class Physics Textbook Page No. 47

Question 5.
Why db different material media possess different values of refractive indices?
Answer:
Refractive index depends on nature of material. So different media have different values of refractive indices.

10th Class Physics Textbook Page No. 48

Question 6.
On what factors does the refractive index of a medium depend?
Answer:
Refractive index depends on (1) Nature of material and (2) Wavelength of light used.

10th Class Physics Textbook Page No. 49

Question 7.
Can we derive the relation between the angle of incidence and the angles of refraction theoretically?
Answer:
Yes, we can derive the relation between angle of incidence and angles of refraction theoretically. We can get nt sin i = n2 sin r.

10th Class Physics Textbook Page No. 53

Question 8.
Is there any chance that angle of refraction is equal to 90° ? When does this happen?
Answer:
Yes, when angle of incidence is equal to critical angle then angle of refraction is equal to 90°.

10th Class Physics Textbook Page No. 54

Question 9.
What happens to light when the angle of incidence is greater than critical angle?
Answer:
When the angle of incidence is greater than critical angle, the light ray gets reflected into denser medium at the interface, i.e., light never enters rarer medium. This phenomenon is called total internal reflection.

10th Class Physics Textbook Page No. 57

Question 10.
How does light behave when a glass slab is introduced in its path?
Answer:
The light ray undergoes refraction two times.

10th Class Physics 5th Lesson Refraction of Light at Plane Surfaces Activities

Activity – 1

Question 1.
Procedure :
Take some water in a glass tumbler. Keep a pencil in it. See the pencil from one side of glass and also from the top of the glass.
Observation:

1. How does it look?
Answer:
From the side it appears to be bent. From the top it appears as it is raising.

2. Do you find any difference between two views?
Answer:
Yes, the position of pencil is different.

Activity – 2

Question 2.
Procedure :

1. Go to a long wall (of length of 30 feet) facing the Sun. Go to the one end of a wall and ask someone to bring a bright metal object near the other end of the wall.
2. When the object is few inches from the wall, it will distort and we will see a reflected image on the wall as though the wall were a mirror.

Observation:

Why is there an image of the object on the wall?
Answer:
The image is due to refraction of light.

Activity-3 Refraction

Question 3.
Procedure: –

1. Take a shallow vessel with opaque walls such as a mug, a tin or a pan.
2. Place a coin at the bottom of the vessel.
3. Move away from the vessel until we cannot see the coin (fig. 2). Ask someone to fill the vessel with water. When the vessel is filled with water the coin comes back into view (fig. 3).

1. Why are you able to see the coin when the vessel is filled with water?
Answer:
The ray of light originated from the coin does not reach your eye when the vessel is empty. Hence you are not able to see the coin. But the coin becomes visible after the vessel is filled with water.

2. How is it possible? Do you think that the ray reaches your eye when the vessel is filled with water?
Answer:
Yes, it reaches the second instance.

3. What happens to the light ray at interface between water and air?
Answer:
It bends towards the normal.

4. What could be the reason for this bending of the light ray in the second instance?
Answer:
It is based on Fermat’s principle, which states that the light ray always travels in a path which needs shortest possible time to cover the distance between the two points.

Activity – 4

Question 4.
Prove that when light ray travels from denser to rarer medium it bends away from the normal.
Answer:


Procedure :

1. Take a metal disc. Use protractor and mark angles along its edge as shown in the figure.
2. Arrange two straws from the centre of the disk.
3. Adjust one of the straws to the angle 10°.
4. Immerse half of the disc vertically into the water, filled in a transparent vessel.
5. Inside the water the angle of straw should be at 10°.
6. From the top of the vessel try to view the straw which is inside the water.
7. Then adjust the other straw which is outside the water until both straws are in a single straight line.
8. Then take the disc out of the water and observe the two straws on it.
9. We will find that they are not in a single straight line.
10. It could be seen from the side view while half of the disc is inside the water.
11. Measure the angle between the normal and second straw. Draw table for various angles and corresponding angles of refraction.

Observation :
We observe that ‘r’ is greater than ‘i’ in all cases and when light travels from
denser to rarer medium it bends away from the normal.

Activity – 6

Question 5.
Why can we not see a coin placed in water from the side of glass?
Answer:
Procedure :

1. Take a transparent glass tumbler and coin.
2. Place a coin on a table and place glass on the coin.
3. Observe the coin from the side of the glass. We can see the coin.
4. Now fill the glass with water and observe the coin from the side of the glass tumber.
5. Now we cannot see the coin because the coin rises up due to refraction.

Activity – 7

Question 7.
Why can we see the coin in water from top? What is the phenomenon behind that?
Answer:

Procedure :

1. Take a cylindrical transparent vessel. Place a coin at the bottom of the vessel.
2. Now pour water until we will get the image of the coin on the water surface.
3. This is due to total internal reflection.

Activity – 8

Question 8.
Write an Activity to find refractive index of glass slab by calculating vertical shift.
(OR)
Explain the experiment with glass slab in determination of refraction through vertical shift.
Answer:

Procedure :

1. Take a glass slab and measure the thickness of the slab.
2. Take a white chart and fix it on the table.
3. Place the slab in the middle of the chart.
4. Draw line around it.
5. Remove the slab from its place.
6. The lines form a rectangle. Name the vertices of it as A. B, C and D. ‘
7. Draw a perpendicular to the longer line AB of the rectangle at any point on it.
8. Place slab again in the rectangle ABCD.
9. Take a needle. Place at a point P in such a way that its length is parallel to the AB on the perpendicular line at a distance of 20 cm from the slab.
10. Now take another needle and by seeing at the first needle from the other side of the slab, try to keep the needle so that it forms a straight line with the first needle. 1 1)
11. Remove the slab and observe the positions of the needles.
12. They are not in same line.
13. Draw a perpendicular line from the second needle to the line on which the first needle is placed.
14. Take the intersection point as Q.
15. The distance between P and Q is vertical shift.
16. We will get the same vertical shift placing needle at different distances.
17. 

AP State Board Syllabus AP SSC 10th Class Biology Solutions Chapter 10 Natural Resources Textbook Questions and Answers.

AP State Syllabus SSC 10th Class Biology Solutions 10th Lesson Natural Resources

10th Class Biology 10th Lesson Natural Resources Textbook Questions and Answers

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Question 1.
The BP Statistical Review of World Energy in June measured total global oil at 188.8 million tonnes, from proved oil resources at the end of 2010. This is only enough for oil to last for the next 46.2 years. What measures should be taken to conserve oil? What will happen if we do not conserve it?
Answer:
Measures to be taken to conserve oil are:

1. Walk, ride a bike, carpool and use public transportation whenever possible.
2. Prefer public transport system like bus or train instead of travelling in personal vehicles.
3. Choose materials other than plastic which uses crude oil for household items.
4. Use cloth or paper bags instead of plastic bags when shopping.
5. Use organic fertilizers for agriculture and gardening because fossil fuels are used in making chemical fertilizers.
6. Produce renewable biofuels to power cars and trucks.
7. Vehicle owners should keep their vehicles serviced i.e., correct amount of air in fires, oil change, spark plug/fuel injector checks, often-at least quarterly.
8. Drive in the correct gear. Incorrect gear shifting can lead to as much as 20% increase in fuel consumption.
9. Consider a hybrid vehicle or an electric vehicle.

If we do not conserve oil, we never get oil after 46-47 years. So all the industries that depend on the oil for energy will break down. Facilities linked with oil will be hampered. So the future generations will suffer.

Question 2.
Here is a news strip, read it carefully and answer the following questions.

Villagers oppose sand mining project Santhabommali (Srikakulam):

People of more than 20 villages in two mandals of Srikakulam have raised a banner of revolt against the proposed beach sand mining project by o private company and threatened to intensify their agitation if the government does not cancel the project. The sand mining is being taken up to extract rich minerals from the area. The villages are located around the forest belt were mining was initiated.

i) Do you think the villagers are doing the right thing to agitate? Why?
Answer:
Yes, the villagers are doing a right thing to agitate. Because beach sand mining leads to certain problems such as –

1. Destruction of natural beaches and ecosystems.
2. Habitat loss for globally important species such as turtles, shore birds, etc.
3. Destruction of nearshore marine ecosystems.
4. Increased shoreline erosion rates.
5. Reduced protection from storms, tsunamis and wave events.
6. Economic losses through tourist abandonment.
7. Loss of coastal aesthetics and
8. Increased saline water intrusion.

The threats posed by sand mining are made even more critical given the prospect of a significant rise in global sea level over the coming decades,

ii) What resources are the villagers trying to save by their agitation?
Answer:

1. Villagers can save the biodiversity of the area by agitating.
2. They can save flora like mangroves and fauna like turtles, gharials (a species of crocodiles) etc.

iii) Will the villagers be benefited by the rich minerals extracted from sand?
Answer:

1. No, the villagers will not be benefitted by the rich minerals extracted from sand.
2. Extraction of minerals may provide employment for few people in that area but most of the local people who are depending on fishing for their livelihood may lose their livelihood as the sand mining brings some disturbances in the ecosystem.

iv) Why does the private company want to carry out mining in the area?
Answer:
Private company wants to carry out mining in that area, for the rich minerals like Titanium and Zirconium. That can be extracted from the sand in the beaches.

v) Does the government have any role to play?
Answer:

1. The government’s role is very important in this regard.
2. It has to make some laws to protect the beaches and their biodiversity.
3. These laws should be implemented very carefully.
4. Indiscriminate and unlawful mining should be prohibited strictly.

vi) How will mining in that piece of land affect people of the area?
Answer:
Mining in that piece of land affects people of the area in many ways.

1. People who depend on tourism may lose their livelihood.
2. People who depend on fishing and other natural products may also lose their livelihood.
3. They may not get proper drinking water due to increased saline water intrusion
4. They may get severe loss whenever natural calamities like tsunamis and storms occur due to reduced protection.
5. In severe cases they have to leave that place due to increased soil erosion and deepening of seashore.

Question 3.
What is sustainable development? How is it useful in natural resource management?
Answer:
Sustainable development: When we use the environment in ways that ensure we have resources for the future, it is called sustainable development.
Useful in natural resources management:

1. Sustainable development ensures the judicial management of natural resources.
2. It helps in optimum utilization of alternative resources and renewable resources.
3. Thus it helps in decreasing the ever increasing demand for fossil fuels and non-renewable resources.
4. Sustainable development practices will give more scope for planning new methods of natural resource management.

Question 4.
Write a detailed note on management of a natural resource.
Answer:

1. Natural resource management refers to the management of natural resources such as land, water, soil, plants and animals, with a particular focus on how management affects the quality of life for both present and future generations.
2. The main goal of natural resource management is sustainability – balancing social, economic and environmental factors to make sure that our children and grandchildren can equally benefit from our natural resources.
3. Our social, economic and environmental well-being depends on the sustainable management of natural resources.
4. Natural resource management deals with managing the way in which people and natural landscapes interact.
5. It brings together land use planning, water management, biodiversity conservation and the future sustainability of industries like agriculture, mining, tourism, fisheries and forestry.
6. Natural resource management specifically focuses on a scientific and technical understanding of resources and ecology and the life-supporting capacity of those resources.
7. The various approaches applied to natural resource management include
   a) Command and control
   b) Community-based natural resource management
   c) Adaptive management
   d) Precautionary approach and
   e) Integrated natural resource management
8. Reduce, Reuse and Recycle are the key concepts for Natural resource management.

Question 5.
Suggest some ways of reusing a resource in your locality.
Answer:
Reusing of a resource (water) in our locality :

1. Washing hands in the garden.
2. Washing machine rinse water can be used for toilet flushing and floor cleaning.
3. Water from washing of fruits and vegetables can be used to water plants.
4. Laundry water can be reused to clean the cars.
5. Even the drain water can also be recycled.
6. After purification recycled water can be used for agriculture.
7. Recycled water can be used to cool down the machinery in the industries.
8. Once used water can be used to recharge the ground water.
   Once used water can be used again like this to conserve the water resource.

Question 6.
Why should we conserve forests and wildlife?
Answer:
We should conserve forests and wildlife for the following reasons.

1. These are the rich habitat for plants and animals (wildlife).
2. Forests are needed for the smooth functioning of biogeochemical cycles.
3. Forests are necessary for the formation of humus and for maintaining soil fertility.
4. Forests serve as lung for the world. They purify air and protect the earth from greenhouse effect and global warming.
5. Many industries such as sport equipment, paper, lac manufacturing, timber and furniture etc., depend on forests.
6. Forests and wildlife provide many fruits, medicines, dyes, sandal wood, bamboo, etc.
7. Forests provide employment to a large number of people and also help in generating revenue.
8. Wildlife act as ‘gene bank’.
9. Conservation of wildlife ensuring that all diverse species in an area survive, breed and flourish.
10. Conservation of forests and wildlife is vital for the ecological stability of a particular area.

Question 7.
Suggest some approaches towards the conservation of forests.
Answer:
The approaches towards the conservation of forests.

1. Sustainable forestry methods should be adapted.
2. Avoiding certain logging techniques such as removing all the high-value trees or all the largest trees from a forest should be avoided.
3. There should be proper laws for the exploitation of forest resources.
4. People should be made more aware about the importance of forests.
5. All possible forest should be announced as the reserve forests.
6. Participation of local people and villagers must be taken in the conservation of forests and they should be given proper employment.
7. Over exploitation by industrial groups and due to the activities of tourist depart¬ment should be checked.
8. There should be incentives and rewards for the efforts made by the people towards the conservation of forests.
9. Overgrazing of forest vegetation by the cattle of local people should be prevented.
10. Measures should be taken to prevent and control forest fires.

Question 8.
Natural resources are decreased more rapidly. Guess what will be the consequences.
What are the consequences of depletion of natural resources?
Answer:
The consequences of rapid decrease of Natural resources.

1. The resources scarcity will arise shortly and demand for them will increase.
2. Future generations may not get these resources.
3. Vehicles running with fossil fuels become useless.
4. All the industries that depend on these sources will shutdown.
5. Electricity production through these sources will be stopped. So we have to stay in dark during night.
6. All the utensils and other articles should be made out of recycled materials.
7. Balance in the nature will be disturbed due to decrease in these sources like forest and biodiversity.
8. We have to search for other sources as the alternative for these resources.

Question 9.
Prepare a questionnaire to conduct interview with petrol filling station personnel about consumption of fossil fuels. (OR)
What questions are you going to ask petrol-filling personnel about consumption of fossil fuels?
Answer:
Questionnaire to conduct interview with petrol filling station personnel about the consumption of fossil fuels:

1. What is the name of the filling station?
2. Where is it located (landmark)?
3. How many litres of petrol is being imported everyday or week or month?
4. How many litres of diesel is being imported?
5. How many two wheelers are being filled everyday here?
6. How many autos are being filled everyday here?
7. How many lour wheelers are being filled everyday here?
8. How many litres of petrol is being sold per day in this filling station?
9. How many litres of diesel is being sold per day in this filling station?
10. What is the total amount of fossil fuel consumed by the people through this filling station per month?
11. Why the rates of petrol and diesel changing everyday?

Question 10.
Prepare model for rain water harvesting or energy saving or soil management. That reflect your innovative thoughts.
Answer:
Rain Water Harvesting:
Procedure to prepare a model for rain water harvesting:

1. Make a model of a house with roof little slanting towards one side.
2. Connect a tube/pipe to the down end such that the rain water that falls on roof can be collected.
   
3. Connect the other end of this tube to a barrel like structure which can be used as storage tank.
4. From the tank arrange a tube towards the garden along with a valve that can be closed and opened.
5. Arrange one more tube with valve into a recharge pit or percolation pit arranged at one corner.
6. Arrange a tap to the tank that can be opened to collect the water for cleaning floor, vehicles etc.
7. During rain, water from roof can be collected into tank and we can utilize it later for gardening or cleaning purposes.
8. When water is in excess it can be used to recharge underground water.

Question 11.
List out names of villages, farmers and procedure followed to the restoration of any natural resource in your area.
(OR)
How villagers and farmers of your village restore natural resources in your area?
Answer:

S.No.	Village name	Farmer’s name	Procedure followed to restoration of natural resources
1.	Kandlagunta	Ch. Ramaiah	Constructed recharge pits to restore under – ground water.
2.	Kotappakonda	B.Bangar Raju	Constructed check dams to restore under – ground water.
3.	Reddy Palem	T. Ranganadh	Recharged the well by building dykes in the nalla.
4.	Uppalapadu	R. Sundaram	Motivated the villagers to construct percola­tion pits.
5.	Nagaram Palem	D. Raja Reddy	Removed silt from the tank.

Question 12.
You might have heard the Natural Gas drillings near Kakinada by ONGC (Oil and Natural Gas Corporation). Collect information and prepare a note on the status of Gas production at the basin.
Answer:

1. Presently ONGC producing gas at the rate of 3.05 MMM³ / day to 4.0 MMM³ / day.
2. ONGC, GSPC, Reliance Industries are companies exploring oil and natural gas in this region.
3. GAIL is marketing and distributing the natural gas through gas collection station.
4. ONGC is associated with GAIL, in planning the additional facilities and technical inputs needed for the future enhanced gas supplies.
5. ONGC has established mini oil refinery at Tatipaka.
6. Total allocation of natural gas from K.G. area is 8.5 MMM³ / day.
7. ONGC has already projected a production potential of 6.5 MMM³ / day of availability of which entire quantity has been allocated to the industrial consume of the area.
8. 16 Industries are actively using Natural gas investing Rs. 5500 crores are working well for power generation, steel re-rolling, producing fertilizers, etc. and some power projections are almost invested Rs. 4000 crores and waiting for a supply of Natural gas.

Question 13.
Does your village or nearest city have a mechanism in place for recycling these waste materials? Find out how it is done and write in detail.
Answer:
Near to our village, there is a center that recycles paper waste. Here the waste paper is recycled in the following way.

1. Waste paper is collected from various sources.
2. This paper is taken to the recycling plant where it is separated into types and grades.
3. The separated paper is then washed with soapy water to remove inks, plastic film, staples and glue.
4. The paper is put into a large holder where it is mixed with water to create slurry.
5. By adding different materials to the slurry different paper products can be created, such as cardboard, newsprints or office paper.
6. The slurry is spread using large rollers into large thin sheets.
7. The paper is left to dry.
8. Then it is rolled up, ready to be cut and sent to the shops.

(OR)

Plastic Recycling process:
Stage – 1: Plastic needs to collected by the recycling company. Once plastic arise recycling plant, the first stage is to sort the plastic into specific types because plastic recycling is more complex than of other metals like glass or paper. Due to many different types of plastic, mixed plastic cannot be used in manufacturing without delivering poor quality products.

Stage – 2: Once the waste plastic is identified and separated, the cleaning process will begin. This starts with washing to remove paper labels, adhesives and other impurities to be completely removed as this lowers the quality of recyclic plastic.

Stage – 3: The shredding stage is when the plastic is taken and loaded on to conveyor belts or directly into huge hoppers, that funnel the clean scrap towards rotating metal teeth that rip the plastic into small pellets which are bagged up and ready for testing.

Stage – 4: Identify and classify the plastic: Once the shredded plastic has been bagged, it is then chemically tested and labelled as to it’s exact specification. This grade plastic can be used as it is by adding to a mix of vergin plastic in a manufacturing run alternatively the grade plastic can be further recycled.

Stage – 5: Extruding: This is the final stage in recyclic plastic. This involves cleaning and melting, shredded plastic and extruding the form of pellets which then go on to manufacture the next lot of plastic products.

Reasons to recyclic plastic:
Millions of tons of waste plastic end up in land fill. When the vast majority of it can be recycled, it is too easy to throw away rubbish without second thought.

But we need to take care of our planet and not just reducing the amount of rubbish we bury but also given that plastic is derived from oil, a natural product with ever depleting resource, it makes sense to recycling as much as possible.

Question 14.
Collect any graph that shows oil (petroleum) consumption in India.
i) Does the production meet consumption in India?
ii) During which period of time shows highest increase in consumption rate?
iii) What will you say happened to production from past ten years, for example, 2004 to 2014?
iv) Suggest some ways to bring down the consumption of petroleum.
Answer:
i) No, the production of oil doesn’t meet the consumption in India.
ii) During 2009 to 2011, there is highest increase in consumption rate.
iii) There was a gradual increase in production from 2001 to 2011. 139.94 million bbl more petroleum was produced in 2011 than 2001. But it does not meet the increased consumption. 1242.27 million bbl more petroleum was consumed in 2011 than 2001. This is nearly nine times more than growth in production.
iv)

1. Using public transport.
2. Walking, using car pool whenever possible.
3. Using hybrid vehicles/electric bikes.
4. Planning alternate source of energy like biofuel.
5. Using products free from petrochemicals like organic fertilizers instead of chemical fertilizer, cloth or paper bags instead of plastic bags etc., can bring down consumption of petroleum.

Question 15.
Proper utilization of natural resources is the way to show gratitude to our nation. Can you support this statement? Give your argument.
Answer:
Yes, I support this statement for the following reasons.

1. Natural resources are our natural wealth which is very essential for our well-being and economic growth.
2. The growth and development of any nation depend on its natural resources and their proper utilisation.
3. We are enjoying the fruits of these resources which is provided by our nation to us.
4. In return, it is our responsibility to safeguard our nation’s wealth.
5. For this it is very essential to utilise these natural resources in such a way that they will remain in our nation and available for the future generations.
6. If we don’t utilize them in proper way there will be crisis for these resources and we have to depend on other nations for it.
7. Such a situation will damage our economy and life standard, for which we are the responsible persons.
8. So, proper utilisation of natural resources is surely the way to show gratitude to
   our nation.

Question 16.
Crop selection and cultivation should be based on the availability of water. Prepare a slogan to make aware of farmers about this.
Answer:

1. See the water availability – Choose the crop.
2. Use micro irrigation – Save water for future.
3. Use less water – Get more productivity.
4. Need based irrigation – Best production.
5. Less water availability – Use dry land crops.
6. Drop by Drop – Grow and grow.
7. Sprinkle water on crop – Crop feels happy.
8. See the water – Grow the crop.
9. Today’s rain water to tomorrow’s life saver.
10. No matter your occupation – Water conservation is your obligation.

Fill in the blanks.

1. ———– plants are used for production of biofuels.
2. Biodiversity is important for more than just food and for ———– also.
3. Example for non-renewable resource is ———–
4. ———– is the alternative method to prevent groundwater depletion.
5. Cultivation of paddy is suitable for ———– areas.

Answer:

1. Jatropha curcas
2. medicines
3. coal, petroleum
4. Water storage structure
5. water rich

Choose the correct answer.

1. Percolation tanks helps to  [ ]
   A) Supply water for agriculture
   B) Increase ground water level
   C) Preserve rain water
   D) Prevent overflow water from tanks during rainy season
   Answer: B/C
2. Which of the following practices is suitable to farmer at less water resources?  [ ]
   i) select short term crops
   ii) cultivate commercial crops
   iii) adapt drip system
   iv) crop holiday
   A) i, iii
   B) i, ii, iii
   C) i, iv
   D) iii, iv
   Answer: B
3. Which of the fossil fuel reserves decrease more rapidly in India?  [ ]
   A) natural gas
   B) coal
   C) petroleum
   D) all
   Answer: C
4. Huge amount of toxic chemicals leak into the surrounding ecosystem because of  [ ]
   A) industries
   B) mining
   C) pesticides
   D) modern technology
   Answer: B
5. Sustainable development means  [ ]
   A) prevention of wastage
   B) stable growth
   C) development without damaging
   D) high yielding in less time
   Answer: C

10th Class Biology 10th Lesson Natural Resources InText Questions and Answers

Table-1: Area under irrigation

Village	Total Area (acres)	Percentage Area Irrigated	Number of Wells	Sample Size
Village -1	3791	25%	155	25
Village – 2	2970	15%	175	25

Question 1.
a) What is the total irrigated area in acres, in Village – 1?
Answer:
The total irrigated area in Village -1 is 947.75 acres.

b) If one needs to irrigate all the land in Village -1 how many wells would be required?
Answer:
Number of wells required to irrigate all the land in Village -1 are 620.

c) Though the number of wells is less in Village -1, the area under irrigation is more as compared to Village – 2. How is this possible?
Answer:
The area under irrigation is more in Village -1 when compared to Village – 2 because the farmers in Village – 1 use water resource jointly and follow micro irrigation techniques.

d) Do you think the area under irrigation will change due to rise in population?
Answer:
No, the area under irrigation will not change due to rise in population.

Table 2: Status after five years

Village	Percentage Change in area under irrigation	Percentage decline in number of wells	Percentage change in area under crops
			Paddy		Cotton	Gingelly	All crops
			K	R			K	R
Village -1	-14	-39	-17	-17	163	86	11	-17
Village – 2	-30	-68	-22	-50	27	138	-05	-50

K stands for Kharif while R stands for Rabi. Negative values indicate loss/ decline, while positive ones show gain/rise.
Question 2.
a) If the number of wells is 155 now, what was it 5 years back ?
Answer:
5 years back nearly 215 wells were there.

b) What do you think ‘decline in number of wells’ represents?
Answer:
Decline in number of wells represents fall of ground water levels due to less rainfall.

c) How would crops be affected due to decline in the number of wells?
Answer:
The crops do not grow well and the yield is less due to decline in the number of wells.

d) Compare table 1 and 2 and state what they tell us about the area under irrigation in both the villages?
Answer:
When compared table 1 and 2 the area under irrigation in Table – 2 is decreased.

e) Which village do you think is more affected?
Answer:
Village – 2 is more affected.
f) What is the change in types of crops grown in the villages?
The crops which need less water and has less duration are grown.

Question 3.
If 45 per cent of wells have dried up in Village -1 and there is 39 per cent decline in number of wells, what percentage of wells do you think have been converted to bore wells?
Answer:
84% of wells have been.converted to bore wells.

Question 4.
By comparing the two villages, find out where greater number of wells dried up? What methods would have saved the wells in other village?
Answer:
By comparing the two villages Village – 2 has greater number of wells dried up. Percolation tank in Village -1 saved the wells drying up.

Question 5.
Which type of farmers, those having small land holdings or those with large land holdings are most affected when wells dry up?
Answer:
The farmers having large land holdings are most affected.

Question 6.
If water resource becomes scarce, will it affect the nature of soil in an area?
Answer:
Yes, it will also affect the nature of the soil in an area.

Question 7.
As wells dry up, how are people in the area dependent on the well affected?
Answer:
Open wells have dried up, water tables have gone down.

Question 8.
Why do you think water became scarce mainly in Village – 2?
Answer:
Water is pumped out of wells and bore wells using electricity leads to water scarcity.

Question 9.
Table 3 : Annual expenditure on well irrigation for small and large farmers(2002)

a) Is the availability of water resource same for a small and a large farmer?
Answer:
Yes the availability of water resource is same for a small and a large farmer.

b) Do you think the availability should be same for everyone in an area?
Answer:
Availability should be the same as the ground water level is same in all places.

c) A well irrigates more area in Kharif season as compared to Rabi, how is it possible?
Answer:
A well irrigates more area in Kharif season as compared to Rabi because Kharif occurs in rainy season and Rabi in winter season. So well irrigation is more in Kharif season.

d) How should a farmer utilize such a condition?
Answer:
Farmer wants to irrigate more land in Kharif season to grow more crop to get more yield.

e) If a well can irrigate 2.5 per cent of cultivable land, how many wells would irrigate whole of the land?
Answer:
The number of wells required to irrigate whole land in Village -1 are around 1516 wells.

f) Which factor has a greater effect on expenditure, number of wells or depth of a well?
Answer:
Depth of a well has greater effect on expenditure.

g) What is the total expenditure on a whole cultivable land owned by a small farmer in Village – 2? How do you think a small farmer meets this expenditure?
Answer:
The total expenditure on a whole cultivable land owned by a small farmer in Village – 2 is around 20,000 – 45,000 rupees per acre per year. The small farmer meets this expenditure through agricultural loans from banks.

h) What could help the small farmer reduce expenditure?
(Hint: Think of crops that require less water)
Answer:
Cultivating the crops which require less amount of water.

i) Do you think increasing the depth of bore well is a good solution for increasing total land area under irrigation? Why/Why not?
Answer:
Increasing the depth of bore well is not a good solution for increasing total land area under irrigation. This is because with increasing depth, expenditure also will increase so net profit will decrease. Moreover, groundwater level decreases much more and has to dig more depth.

Question 10.
Table 4: Income on crops

Village	Type of Farmer	Net income per acre in Rupees				Total income per acre year in rupees
		Paddy Kharif	Paddy Rabi	Cotton	Gingelly
Village -1	Large	8200	8700	4900	3300	25100
	Small	7046	8490	10889	3110	29535
Village – 2	Large	10698	5970	4000	3595	24263
	Small	9128	7380	3031	2650	22189

a) Which crop is most profitable for a small farmer in Village – 2?
Answer:
For a small farmer in Village – 2 paddy in Kharif Is more profitable.

b) What is the difference between a small farmer in Village – 1 and Village – 2?
Answer:
Small farmer in village -1 is getting more income than farmer in Village – 2.

c) Which crop could replace paddy and the profitable as well for a small farmer in Village – 1?
Answer:
Cotton crop could replaces paddy, it is more profitable than others.

d) Though we know that paddy consumes maximum water, why do you think farmere still like to grow paddy?
Answer:
Though paddy consumes maximum water, farmers believe that it is profitable and less risky. It Is a staple food for people. So they still like to grow paddy.

e) What is the impact of a depleting resource upon the farmers?
Depleting resource increases the cost of production. So the farmers are becoming poor and poor as cost increases and profit or income decreases.

f) Do you think the income of a small farmer in Village – 2 is sufficient enough to meet his expenditure?
Answer:
No, the income of a small farmer in Village – 2 is not sufficient enough to meet his expenditure.

g) What are the major causes of pitiable condition of small farmers at Village – 2?
Answer:
The major causes of pitiable condition of small farmers at Village – 2 are

1. Lack of awareness regarding sustainable use of natural resources like water.
2. Not adopting crops suitable to their conditions.

h) Do you think farming as an occupation is profitable for the small farmer in Village – 2?
Answer:
No. Farming as an occupation is not profitable for the small farmer in Village – 2.

i) Would the farmer have to look for other kind of occupations to meet his needs?
Answer:
No need to look for other kind of occupations to meet their ends, but has to select proper crops that requires less water, proper methods that increase ground water, proper devices to use water discriminately.

j) How did the availability of water affect a small farmer at Village – 2?
Answer:
The availability of water affected the average household income at Village – 2 For them farming is not profitable. As their income is less than the life standards of these people will also be less.

Question 11.
How can wells be recharged ?
Answer:
Percolation pits helped in reacharging dried up bore wells. Dykes or barriers are constructed to build underground streams.

Question 12.
How would recharging dried up wells help farmers of Village – 2?
Answer:
In Village – 2 the recharged dried up wells build up under ground streams to tap underground water optimally.

Question 13.
What does the case tell us about a water resource and its effect on farmers?
Answer:
The case tells us that water should not be used indiscriminatly. Every water drop in the ground is important.

Question 14.
How do you think we can use water judiciously?
Answer:
The amount of fresh water is in small amounts only 2.5 – 2.75%. So we should use water carefully.

Question 15.
Why were farmers at Village – 1 at a better state than those at Village – 2?
Answer:
Farmers were at Village -1 at a better state than those at Village – 2 because the farmers of Village -1 have plenty of water to grow their crops.

Question 16.
How did farmers of Village – 2 and Village -1 recharge their ground water resources?
Answer:

1. The farmers of Village – 2 and Village -1 recharge their ground water resources by construction of soak pits.
2. The soak pits to tap rain water and by construction of dykes, they increased the ground water levels.

Question 17.
What other ways of restoration of a resource does the Kothapally case tell us about?
Answer:
Broad bed furrows land form and contour planting are the other ways of restoration of a resource.

Question 18.
What are some common means of restoration and conservation of water resource that we came across in the cases studied so far?
Answer:
Planting Gliricidia on field bunds to restrengthen and make soil nitrogen rich. Farmers were encouraged to use water resource jointly and irrigate land using micro irrigation techniques.

Question 19.
What do you think will happen if we do not take care of the sources of water?
Answer:
If we do not take care of water resources, they get replenished.

Question 20.
How do you think we will meet our requirements in future?
Answer:
We have to meet our requirements in future by

1. Desalenating the sea water
2. Restoring of ground water by recharging with rain water.
3. Getting cooperation from the neighbouring states and
4. Conserve water now for future.

Question 21.
Do you think we would have to depend upon other states or perhaps other countries as well?
Answer:
Yes, we would have to depend upon other states for water.

Question 22.
Could the amount of water used for irrigation in our state be reduced? How?
Answer:
The amount of water used for irrigation in our state could be reduced by following micro irrigation techniques like drip irrigation, sprinkles, etc., and by growing crops that require less amount of water.

Question 23.
Does cropping pattern have any role to play in reduction of water utilisation?
(Hint: Think of the case of Village – 2 and Village -1).
Answer:
Yes, cropping pattern have role to play in reduction of water utilisation. Broad bed furrow, land form and contour planting helps in reduction of water utilisation.

Question 24.
Do you think one needs laws for distribution of water and its use? Why/Why not?
Answer:

1. Yes, laws are needed for distribution of water and its uses.
2. Otherwise all the people may not have self discipline to conserve water.
3. As water is a key resource for life competition may arise between people or states or countries.
4. Laws help to control this kind of disputes and use it judiciously.

Question 25.
How much per cent of area do you think is irrigated by other sources of water?
Answer:
Five per cent of area in our state is irrigated by other sources of water.

Question 26.
Why is it important to recharge the ground water sources?
Answer:

1. Recharge of the ground water sources is very important.
2. This is because nearly 43% of irrigating land is getting water from ground.
3. Due to over drilling of bore wells and pulling out the water by using electric motors, the ground water level is decreasing day by day.
4. If it goes on without recharging, ground water becomes scarce.
5. It shows a vast impact on agriculture and the productivity will decrease.
6. Flourine level in ground water will increase.
7. Saline water may intrude in to the interior places of land and water becomes unfit for both drinking and agriculture.
8. Farmers have to drill the bore wells to the more depths which increase the losses for them.

Question 27.
Why do the rivers fail to benefit the state to an extent they should have?
Answer:
Rivers fail to benefit the state to an extent they should have. Because

1. There are no sufficient structures (dams) to store river water.
2. Over usage of water by the other states.
3. Geographically our rivers are flowing through the rocky and hill areas in most of the places in our state where it is difficult to make canals.
4. The government should plan for proper utilization of river water after scientific study with the help of expert engineers.

Question 28.
Since ground water resources are getting depleted at a fast pace what are the alternatives?
Answer:
Since ground water resources are getting depleted at a fast pace we have to construct percolation tanks to collect run off water. Water shed management projects should be adopted to renew the ground water levels.

Question 29.
River Godavari fails to provide water for the projects like Sri Rama Sagar in Telangana due to over usage of water by some other state. How should states and countries work to provide enough for all?
Answer:
States and countries should work to provide enough water for all by allotting water to other states or countries in an emicable atmosphere.

Question 30.
What would you do to motivate others to manage an important resource in your locality?
Answer:
To motivate others manage an important resource in my locality I will do the following activities:

1. I will explain the importance of resource and need for its proper management.
2. I will conduct the seminars on this issue.
3. With the help of my friends and teachers I will conduct some competitions like debate, essay writing, etc., on this issue.
4. I will plan some cultural activities such as songs, skits that explain the importance of managing the resource and exhibit them in the school and the village to motivate the village.

Question 31.
How did the villagers in Kothapally resort to sustainable management
Answer:

1. The villagers in Kothapally resort to sustainable management with the help of ICRISAT.
2. ICRISAT educated villagers by large and provided technical support for cost-efficient water storage and soil conservation structures.
3. The measures were community as well as individual farmer-based.
4. Fourteen water storage structures with the storage capacity of 300 to 2000 m³, 60 mini percolation pits, field bunding on 38 hectares were completed.
5. Twenty-eight dry open wells, near Nalla were recharged by building dykes in the Nalla and retaining the run off rain water in it.
6. A user group was formed for each water storage structure and the water collected was exclusively used for recharging the ground water to the dried well.
7. Broad bed furrow land form and contour planting was implemented to conserve soil and water.
8. Gliricidia plants are planted on the field bunds to strengthen the land, make the soil nitrogen rich.
9. Farmers were encouraged to use water resource jointly and irrigate land using micro-irrigation techniques.
10. Saplings of useful species were planted along the roads, field bunds and Nallas.

Question 32.
Why do you think forests are important?
Answer:
Forests are important because,

1. They are rich habitat for plants and animals.
2. They serve as a lung for the world.
3. They purify air, decrease carbon dioxide, global warming and green house effect.
4. Thus provide various valuable things such as wood, medicines etc.
5. They are providing raw materials for several industries.
6. They maintain ecological balance in nature.
7. They preserve the soil fertility.
8. They cause rains.

Question 33.
Observe a lawn in your area (if you have one) and see how it is maintained. Find out from the gardener the different types of plants that he removes from time to time. Do you think a farmer does the same thing on his farm?
Answer:
The gardener removes all the species of plants that grow in the lawn from time to time.
Farmer does the same thing on his farm. But the variation is all the plants are removed from lawn just for pleasant look whereas farmer remove only weed plants that compete with the crop plants for space, nutrients, water and sunlight. This is to increase the productivity of crop plants.

Question 34.
What do fossil fuels provide us?
Answer:

1. Fossil fuels provide us energy.
2. This energy can be used for various purposes such as running vehicles, machinery in industries, etc.
3. They are also useful in the production of electricity.
4. They also provide petrochemicals which are helpful in the manufacturing of several products that include plastics, synthetic rubber, fabrics like nylon, medicines, cosmetics, waxes, cleaning products, medical devices, etc.
5. They also provide energy for cooking, lighting, etc.

Question 35.
Why do we need to conserve the fossil fuels?
Answer:

1. Fossil fuels are non-renewable resources.
2. If once they are used up, they never replenish again or take several thousands of years to replenish.
3. They become integral part of our life, that we cannot live without these.
4. So, we need to conserve fossil fuels so that we don’t run out of them.

Question 36.
Collect information about solar, wind, tidal and water power and prepare a scrap book.
(OR)
Collect information about conventional energy sources from internet and prepare a note on it.
Answer:
Solar energy: To use solar energy is to generate electricity from sun light. For this purpose special chemical substances which are sensitive to light have been developed.
When light falls on these substances small chemical current is generated in large amounts. This can be stored and used when needed.
Watches, calculators, street lamps have been invented which use the current produced by light falling on light sensitive material.
Wind Energy: Wind mills are in use for centuries especially for pumping water from wells.
In wind mills, wind rotates the blades of windmill and is used to move the piston and lift the water from the well.
Wind energy is being used to pump water and to run turbines for the production of electricity.
Tidal energy (Kinetic energy) : Large amount of energy (Kinetic energy) la stored In the waves especially In seas.
Special devices have been made to rotate as the water passes through them by the wave action.
This Is used to generate electricity.
Water power: Dams are constructed across the rivers water from the reservoir falls from a height on the turbines.
This water falls Is used to drive turbines to generate electricity. These are called hydro electric projects.

Question 37.
Ask your teacher about nuclear energy and its impacts on ecosystem.
Answer:
Nuclear energy is produced by splitting the nucleus of an atom of elements like uranium or plutonium. This process Is called fission.
Another process for production of nuclear energy Is by fusion. In this process two nuclei of the same elements are fused with one another. In this process more energy is produced than by fission.
The energy Is produced as heat. This Is used to produce steam which runs generators to produce electricity.

Question 38.
Think why disasters like Uttarakhand happened?
Answer:

1. Uttarakhand and Himachal Pradesh are two hill states that were stuck by extreme rains in 2013.
2. Heavy rainfall has wrecked havoc on the region because of fragile nature of Himalayan range and poor soil stability in its deep steps. But it is the man made factor that has compounded the scale of the disaster.
3. Unabated expansion of hydro power project and construction of roads to accommodate ever-increasing tourism especially religious tourism are also major causes for the unprecendented scale of devastation.
4. The valleys of Yamuna, Ganga and Alakananda attract heavy traffic of tourists. For them, government has to construct new roads and widen the existing ones.
5. A new mountain range like Himalayas will remain study if not tampered much. But the huge expansion of trade and transport is bringing the mountains in Uttarakhand down.
6. Study should be conducted to assess the carrying capacity of the Himalayas and development should be planned accordingly.

Threat from dams: The Ganga in upper reaches has been engineers’ play ground. The central electrical authority and Uttarakhand power department have estimated the rivers hydrolytic potential at some 9000 muc and planned 70 odd projects on its tributaries. In building these, key tributaries have been modified through diversions through tunnels or reservoirs.

Question 39.
Do you think it is necessary to have a lot of lighting for decoration during celebrations?
Answer:
No, it is not necessary to have a lot of lighting to decorate an occassion of celebration. It is mere waste of electricity and money. We should conserve electricity for proper use.

Question 40.
What other things could you reuse to save our resources?
Answer:

1. Glass, paper, wax, plastic, etc., can be reused to save our resources.
2. Recycle: By recycling the waste materials we can reduce pollution.
   Ex : Plastic recycling is a tricky process and can cause havoc.
3. Plastic needs to be carefully stored before it can be processed.

Question 41.
Why should one sort wastes carefully before discarding them from home?
Answer:

1. Before discarding the waste materials we should sort out the reusable things and recycling things.
2. If it is undecayable waste like glass or plastic we can discard them or if they are the decayable waste we can prepare a compost pit to enrich the soil.

Question 42.
Often we keep a plastic bag in our dustbins to discard waste, is it a good practise?
Answer:

1. No, it is not a good practise to discard waste in a plastic bag.
2. When we threw the waste along with the plastic bag it takes hundreds of years for the plastic to get destroyed in the soil and the soil gets polluted.

Question 43.
Can international, national or state organisations alone manage a resource? Who are all involved in the whole process of management?
Answer:
Along with international, national or state organisations there is private organisation named International Union for the Conservation of Nature founded by private groups.

Question 44.
Suggest some ways in which you and your Mends would like to manage a resource.
Answer:
By practising four R’s-reduce, reuse, recycle and recover the things, preparation of recharging structures for water, protecting the wild life and habitats we can manage the resources.

Question 45.
Are we also an important resources of nature? How?
Answer:

1. Yes, we are also an important resources of nature.
2. Human beings, through the labour they provide and the organizations their staff are also considered to be resources.
3. The term human resources can also be defined as the skills, energy, talent, abilities, and knowledge that are used for the production of goods or the rendering of service.
4. In a project management context, human resources are those employees responsible for undertaking the activities defined in the project plan.

Question 46.
Find out the usage of water in litres per day in your home? Do you actually require that much water and how much water is enough in accordance with National standards?
Answer:

1. In my house 900 litres of water is being used per day at the average of 225 litres for a person per day (4 members family).
2. Actually this much water is not required.
3. We can conserve at least 400 – 500 litres of water at the average of 100 to 125 litres per head.
4. In India, the design of water supply system has been done using certain standards.
5. Currently the standard being used is BIS 1179 : 1993, reaffirmed in 1998.
6. According to this, for communities with a population between 20,000 to 1,00,000 – 100 to 150 litres per head per day can be considered.
7. For communities with population over 1,00,000 – 150 to 200 litres per head per day can be considered.
8. On the whole, at an average of 150 litres per head per day is enough in accordance with National standards.

10th Class Biology 10th Lesson Natural Resources Activities

Activity – 1

Study the different ways in which water is used, misused and recycled in the area where you stay. Prepare a questionnaire with the help of your friends and teacher and study at least five households in your locality for the same. Also explore and discuss ways to provide water for all.
Answer:
Ways in which water is used:

1. Drinking
2. Bathing
3. Washing clothes
4. Cleaning utensils
5. For plants in garden and agriculture, etc.

Ways in which water is misused:

1. Not closing the taps after using.
2. Contaminating the water.
3. Brushing near open taps.
4. Getting bath under shower.
5. Playing with water.

Ways in which water is recycled:

1. Allowing the water used in kitchen for garden.
2. Using the once used water to wash vehicles.
3. Using the water from bathing for toilet flush.
4. Washing hands in plant pots.

Questionnaire:

1. For what purposes water is being used in your home?
2. From where this water is being collected?
3. Are you using water only for the needed things?
4. Are you closing taps properly after using?
5. Are you getting shower bath?
6. Are you using more water than required for cleaning, bathing etc?
7. Are there any leaks in your water pipelines?
8. Are you recycling the once used water?
9. In what way are you recycling the water?
10. What measures do you suggest to conserve water and make it available for all?

Ways to provide water for all:

1. Wastage of water should be strictly minimised.
2. Washing hands in the plant pots.
3. Rain water should be directed into recharge pits.
4. Care should be taken to prevent leakage of water from pipes and taps.
5. Wash clothes in running water canals if possible.
6. Direct the kitchen water free from soap and detergents to the garden.
7. Use the soap and detergent water for toilet flush or cleaning vehicles.
8. Recycling of water can be done on large scale in towns and cities and can be utilised again.
9. Cooperation between the states through which a river passing is very essential for providing water for all.
10. People should be motivated in such a way that each drop of water is life and should conserve it.

Activity – 2
i) Find out how many different types of insects are present in and around your house.
Answer:
We find different types of insects present in and around our house.

ii) Do you find the same type of insects in all seasons ?
Answer:
No. We find different types of insects in different seasons.

iii) Make a chart of insects and note their occurrence for at least a week in each season.
Answer:
Ants – All seasons particularly in summer for collection of food.
Butterflies – Winter, summer – Collecting nectar
Honeybee – Winter, summer – Collection of honey.
Beetles – Winter, summer – Collection of food grains
Cockroaches – All seasons – Food and shelter

Activity – 3
Nowadays people are revolt against mining. Collect any such’ incident of our state or neighbouring states from your school library or newspapers and conduct seminar on it’s impact.
Answer:

1. People living in hill top hamlets in seven mandals of Visakhapatnam and East Godavari districts are up in arms against laterite mining in Nagulakonda hill range.
2. Laterite is a raw material used by cement factories.
3. Huge deposits of laterite worth hundreds of crore rupees are found in Nathavaram and Kowur mandals in Visakhapatnam and Pratthipadu, Yeleswaram, Sankhavaram, Routulapudi and Kotananduru in East Godavari.
4. All these mandals are technically coming under scheduled areas.
5. If the mining continues here, it will badly threaten the ecology of that area.
6. The tribal people in that area will lose their livelihood.
7. To reach the mining area road should be laid in the reserve forest area.
8. This leads to depletion of forest resources also.
9. Health of the local people will be badly affected due to the dust spread during mining.
10. Keeping all these in mind the tribal people are opposing the mining in that area.

 

AP State Board Syllabus AP SSC 10th Class Biology Solutions Chapter 9 Our Environment Textbook Questions and Answers.

AP State Syllabus SSC 10th Class Biology Solutions 9th Lesson Our Environment

10th Class Biology 9th Lesson Our Environment Textbook Questions and Answers

Improve your learning

Question 1.
What happens to the amount of energy transferred from one step to the next in a food chain?
Answer:

1. Energy is transferred along food chains from one trophic level to the next.
2. The amount of available energy decreases from one stage to the next.
3. This is because not all the food can be fully digested and assimilate.
4. Hair, feathers, insect exoskeletons, cartilage and bone in animal foods, cellulose and lignin in plant foods cannot be digested by most animals.
5. These materials are excreted or made into pellets of indigested remains.
6. Assimilated energy is available for the synthesis of new biomass through growth and reproduction.
7. Organisms also lose some biomass by death disease or annual leaf-drop.
8. Moreover at each tropic level, organisms use the most of the assimilated energy to fulfill their metabolic requirements – performance of work, growth and reproduction.
9. Most of the energy is lost in the form of heat during biological processes.
10. Only a small fraction goes to the consumer at next tropic level.

Question 2.
What do pyramids and food chain indicate in an ecosystem?
Answer:

1. The ecologists used the idea of pyramid to show relationship among organisms in an existing food chain.
2. Ecological pyramids are of three types. They are pyramid of biomass, pyramid of number, pyramid of energy.
3. Pyramid of biomass indicates the available biomass in an ecosystem; pyramid of number indicates the organisms present and pyramid of energy indicates the available energy in an ecosystem.
4. The food chain in an ecosystem indicates how energy is transferred from one organism to another.
5. The starting point of a food chain are producers and it ends with top carnivores.
6. A food chain represents a single directional transfer of energy.

Question 3.
Write a short note on pyramid of number for any food chain. What can we conclude from this pyramid of numbers?
i) tree ii) insect iii) woodpecker
(OR)
What is a pyramid of numbers? Write a brief note on the pyramid of numbers with the help of a block diagram.
Answer:
a.

1. The number of organisms in a food chain can be represented graphically in a pyramid of number.
2. Each bar represents the number of individuals at each tropic level in a food chain.
3. In the pyramid of numbers, from the first – order consumers to the large carnivores, there is normally an increase in size, but decrease in number.
4. For example, in a wood, the aphids are very small and occur in astronomical numbers.
5. The ladybirds which feed on them are distinctly larger and not so numerous.
6. The insectivorous birds which feed on the ladybirds are larger still and are only present in a small numbers, and there may only be a single pair of hawks of much larger size than the insectivorous birds on which they prey.

b.

1. In the given pyramid, the producer is a large tree, primary consumers are small
   insects which are numerous in number and secondary consumers are woodpeckers which are comparatively less in number than insects.
2. From this pyramid of number, we can conclude that sometimes the pyramid of numbers does not look like a pyramid at all.
3. This could happen if the producer is a large plant or if one of the organisms at any tropic level is very small.
4. Whatever the situation, the producer still goes at the bottom of the pyramid.

Question 4.
What is biomass? Draw a pyramid of biomass for the given food chain.
i) grass leaves ii) herbivores iii) predators iv) hawk
Answer:

1. Biomass is organic material of biological origin that has ultimately derived from the fixation of carbon dioxide and the trapping of solar energy.
2. This includes trees, shrubs, crops, grasses, algae, aquatic plants* agricultural and forest residues and all forms of human, animal and plant waste.
3. Any type of plant or animal material that can be converted into energy is called “Biomass”.
4. 

Question 5.
How is using of toxic material affecting the ecosystem? Write a short note on bioaccumulation and biomagnifications.
Answer:

1. Use of toxic materials such as pesticides, herbicides and fungicides creates new problems in the ecosystem.
2. As these toxic materials are often indiscriminate in their action and vast numbers of other animals may be destroyed.
3. Some of them may be predators which naturally feed on these pests, others may be the food for other animals.
4. Thus causing unpredictable changes in food chains and upsetting the balance within the ecosystem.
5. Some toxic substances have a cumulative effect.
6. Some of them are degradable, can be broken down into harmless substances in a comparatively short time usually a year.
7. Others are non-degradable which are potentially dangerous as they accumulate in the bodies of animals and pass right through food web.
8. This process of entering of pollutants in a food chain is known as “Bioaccumulation”.
9. The tendency of pollutants to concentrate as they move from one tropic level to the next is known as “Biomagnifications”.

Question 6.
Should we use pesticides as they prevent our crop and food from pests or we should think of alternatives? Write your view about this issue and give sound reason for your answer.
(OR)
Why should we think of alternatives to pesticides? Give reasons.
Answer:

1. We should think of alternatives. This is because these pesticides are toxic chemical whose usage leads to Bioaccumulation and Biomagnifications.
2. When we use pesticides, they prevent our crop and food from pests effectively but indiscriminately destroys a vast number of other animals.
3. This is causing unpredictable changes in food chains and upsetting the balance within the ecosystem.
4. Most of the chemical pesticides that contain mercury, arsenic or lead are non -degradable.
5. They enter into food chain, accumulate in the bodies of animals and pass right through food web.
6. Being further concentrated at each step until animals at the top of the pyramid may receive enough to do considerable harm.
7. This is one of the reasons for ever decreasing number of butterflies, bees, small and large birds.
8. Some of the pesticides are nerve poisons and might bring about changes in behaviour.
9. As the human beings are at the end of the food chain, these pesticides may get accumulated in our bodies also. This shows some adverse effects on us, when their concentration becomes sufficiently high.

Question 7.
What is a tropic level? What does it represent in an ecological pyramid?
Answer:

1. The various steps in a food chain at which the transfer of food takes place is called tropic level.
2. Tropic level means the feeding level of the organism.
3. In an ecological pyramid, the first tropic level represents the primary producers, and their number, biomass or energy.
4. Second tropic level represents the herbivores or primary consumers and their number, biomass or energy.
5. The tropic level represents the lower carnivores or secondary consumers and their number, biomass or energy.
6. The fourth tropic level represents the higher carnivores or tertiary consumers and their number, biomass or energy.

Question 8.
If you want to know more about the flow of energy in an ecosystem, what questions do you ask?
Answer:
I will ask the following questions to know more about flow of energy in an ecosystem.

1. How does the energy flow in an ecosystem from one organism to other?
2. Is the energy transformation from one level to other 100% efficient?
3. What per cent of energy transfers from one level to other?
4. What happens to the remaining energy?
5. How does the ecosystem lose its energy during energy transformation?
6. Which tropic level in an ecosystem has more energy and which has less?
7. What is the ultimate source of energy in an ecosystem?

Question 9.
What will happen if we remove predators from food web?
Answer:

1. Removal of organisms from any tropic level of a food chain or food web disturbs the ecosystem and leads to ecological imbalance.
2. If we remove predators from food web, the prey population will increase enormously as there is no natural control over them.
3. The producers population will decrease rapidly as the organisms feeding on them increase.
4. After few generations the prey population also begins to decrease as some of the preys begin to die due to starvation.
5. Some adaptations may also be developed by the organisms to bring the ecological balance.
6. But it may take some generations, till that the ecosystem will be disturbed and imbalanced.
7. For example, if we remove all the predators (carnivorous) from a forest ecosystem, the herbivorous animal population will increase as there are no carnivores to hunt them.
8. As a result plant population will decrease as the ever increasing herbivores feed more and more on plants.
9. After some generations the herbivore population begins to decrease as the decreasing number of plants are not sufficient to feed.
10. Then some herbivorous animals may adapt to feed on other herbivores to increase their survival.
11. Then scope for survival will increase for plants again which leads to ecological balance.
12. But this may take lot of time to evolve new predators and to form ecological balance.

Question 10.
Observe a plant in your kitchen garden, and write a note on producer-consumer relationship.
Answer:
When I observe a plant in kitchen garden, I came to know the following things.

1. Though it may be relatively small, a garden is a complete ecosystem.
2. It has the same components as any other large and elaborate ecosystems had.
3. The plant in a kitchen garden is a producer as it produces their own food from sunlight.
4. There are two types of consumers in this ecosystem, a) Primary consumers and b) Secondary consumers.
5. Primary consumers feed on plants. This tropic level consists of caterpillars, bees and butterflies.
6. Secondary consumers feed on primary consumers. This tropic level consists of birds, garden lizards and spiders.
7. Fungi, bacteria, insects and worms make up decomposers.
8. The producer and consumer relationship can be shown in the following food chain.
   Plant → Plant eaters such as caterpillars, bees, butterflies → Meat-eaters such as birds, garden lizards, spiders
   Producers → Primary consumers → Secondary consumers
9. The pyramid of number appears like this.
   
10. The pyramid of Biomass appears like this
    
11. The pyramid of energy appears like this
    

Question 11.
What type of information do you require to explain the pyramid of biomass?
Answer:
To explain the pyramid of biomass, we require the following information.

1. The type of ecosystem.
2. Producers in the ecosystem.
3. Primary consumers in the ecosystem.
4. Secondary consumers in the ecosystem.
5. Tertiary consumers in the ecosystem.
6. Number of organisms at each tropic level.
7. Size of organisms at each tropic level.
8. Weight of organisms at each tropic level.
9. All forms of waste produced at each tropic level and
10. In total, total amount of biomass produced at each tropic level.

Question 12.
Draw a pyramid of numbers considering yourself sis top level consumer. Pyramid of numbers
Answer:
Pyramid of numbers
Ex: 1

Ex: 2

Question 13.
Prepare slogans to promote awareness in your classmates about eco-friendly activities.
All the living things have the right to live on this earth along with us. Prepare slogans to promote awareness in public about the conservation of biodiversity.
(OR)
Which slogans do you prefer to promote awareness in your locality about eco-friendly activities?
Answer:

1. Live and let live.
2. If we protect the environment, it protects us.
3. Conserve nature – Conserve life.
4. Save mother earth.
5. Earth needs you.
6. Go ecofriendly.
7. Clean the environment, live happily.
8. Heal our planet! Turn it into a better planet.
9. Plant a tree for your environment.
10. Think ecofriendly and live ecofriendly.
11. Earth enables you to definitely stand. Allow it to stand the actual way it is.
12. You’ve only got one planet. Don’t trash it.

Question 14.
Suggest any three programmes on the prevention of soil pollution in view of avoiding pesticides.
(OR)
Suggest any four eco-friendly methods for prevention of soil pollution in view of avoiding pesticides. (OR)
In your area, soil is polluted by the enormous usage of pesticides. Suggest any two programmes for the prevention of soil pollution.
Answer:
To prevent the soil pollution caused by pesticides following programmes should be implemented.

1. Rotation of crops :
   1. Same crop should not be grown in the same field in successive seasons.
   2. Rotation of crops reduce occurance of pests and damage due to pests will be decreased.
2. Biological control: Introducing natural predator or parasite of the pest.
3. Sterility: Sterilising the males of a pest species reduces the population of pests.
4. Genetic strains: The development of genetic strains which are resistant to certain pest.
5. Studying the life histories of the pests: When this is done it is sometimes possible to sow the crops at a time when least damage will be caused.

Choose the correct answer.

1. What does a food chain always start with?
   A) The herbivore
   B) The carnivore
   C) The producer
   D) None of these
   Answer: C
2. Which of the following do plants not compete for?
   A) Water
   B) Food
   C) Space
   D) All the above
   Answer: B
3. Ban all pesticides, this means that
   A) Control on the usage of pesticides
   B) Prevention of pesticides
   C) Promote eco-friendly agricultural practices
   D) Stop biochemical factories
   Answer: C
4. According to Charles Elton
   A) Carnivores at the top of the pyramid herbivore
   B) Energy trapping is high at the top of the pyramid
   C) No producers at the top of the pyramid
   D) A and C
   Answer: D

10th Class Biology 9th Lesson Our Environment InText Questions and Answers

Question 1.
Are all terrestrial ecosystems similar?
Answer:

1. No. All the terrestrial ecosystems are not similar.
2. Basing on variations in climatic conditions such as rainfall, temperature and the availability of light, there are various kinds of ecosystems.
3. The major types of terrestrial ecosystem are
   1. Tundra,
   2. Coniferous forest,
   3. Deciduous forest,
   4. Savannah,
   5. Tropical forest and
   6. Deserts.

Question 2.
If we want to show a food chain consisting of grass, rabbit, snake and hawk then connect the given picture of organisms by putting arrows and make a food chain.
A) Name the producers and consumers in the above food chain.
B) Try to guess what does the arrows marked by you are indicate?
C) Identify at least four other food chains from your surroundings. Name the producers and different levels of consumers in those food chains.
Answer:
Grass → Rabbit → Snake → Hawk
A) In the above food chain grass is the primary producer. Rabbit is the primary consumer, snake is the secondary consumer and hawk is the tertiary consumer.
B) The arrows indicate the flow of energy from one organism to another. So these are always pointed from the food to the feeder.
C)

1. Plant → insect → frog → bird
2. Plant → insect →  frog → snake
3. Aquatic plants → insects → fish → crane
4. Plant → mice → snake → vulture
5. Plant → aphids → spiders → birds

Question 3.
Why do most of the food chains consists of four steps?
Answer:

1. Most of the food chains are quite short and mostly consists of four steps.
2. This is because only 10% of the energy present in a tropic level transfers to the other tropic level.
3. Remaining energy is dissipated as heat produced during the process of respiration and other ways.
4. Thus about three steps in a food chain very little energy is still available for use by living organisms.

Question 4.
Why do the number of organisms get decreased as we move from producer to different level of consumers?
Answer:

1. As we move from producers to different levels of consumers the energy available will decrease gradually.
2. Only ten per cent of the energy present in one tropic level transfer to another tropic level.
3. Biomass also decreases gradually as only 10 – 20% of the biomass is transferred from one tropic level to the next in a food chain.
4. As there is less energy & less biomass available at top levels, number of organisms also less, generally.
5. So, the number of organisms get decreased as we move from producer to different level of consumers.

Question 5.
Draw the pyramid of number for the following food chains.
i) Banyan → insects → woodpecker
ii) Grass → rabbit → wolf
A) Are the pyramid of number having same structure in both of the above two cases as compare to the example given in the earlier paragraph?
B) If there is a difference, then what it is?
Answer:

A) No. The pyramid of number in the above two cases doesn’t have the same structure as compared to the example given in the textbook.
B)

1. In the example (given in the textbook), number of organisms at producers level is more. This number gradually decreased in consumers level step by step. So the pyramid of number formed has typical pyramid shape with broad base and the narrow apex.
2. But in the first case given here, on a single Banyan tree, a large number of insects live and feed. These insects become food for few Woodpeckers. So producers number is less than primary and secondary consumers, and secondary consumers are less than primary consumers. So the pyramid of number does not look like a pyramid. It consists of narrow base, broad middle part and medium apex.
3. In the second case, grass which are large in number become food for few rabbits. Rabbit provides food for several wolves which are comparatively less in number than grass. So primary consumers are less in number than secondary consumers and producers. So the pyramid of number for this food chain also does not look like a pyramid. It consists of broad base, narrow middle part and medium apex. Thus it differs from case (i) also.

Question 6.
Think why the pyramids are always upright?
Answer:

1. In ecology not all the pyramids are always upright.
2. Pyramid of number may be upright, inverted or partly upright.
3. Pyramid of biomass may be upright or inverted.
4. But the pyramid of energy is always upright.
5. This is because energy will decrease when we move from producers to the high level consumers.
6. Only 10% of the energy from one tropic level transfers to the other through food chain.
7. So the energy at base is more, gradually decreases, and very less at the top.
8. As a result the energy pyramid is always upright.

Question 7.
Observe the data given in the following table.

Classes	Area in 1967(Km2)	Area in 2004 (Km2)
Lake – water spread area	70.70	62.65
Lake with sparse weed	0	47.45
Lake with dense weed	0	15.20
Lake-liable to flood in rainy season	100.97	0
Aquaculture ponds	0	99.74
Rice fields	8.40	16.62
Enchrochment	0.31	1.37
Total	180.38	180.38

i) In which year lake-water spread area is more? Why?
Answer:
In the year 1967. Because lake was not brought under cultivation.

ii) How do you think weeds are more in the lake?
Answer:
Excessive nutrient addition, especially from anthropogenic sources, led to explosive weed growth. Ex: Eichornia, pistia.

iii) What are the reasons for decrease in lake area?
Answer:

1. In 1996, almost entire lake was brought under cultivation.
2. Industries came along in ever growing intensity in the catchment area of the lake.

iv) How do the above reasons lead to pollution?
Answer:

1. Consequently, the drains and rivulets carry substantial quantity of various types of pollutants into the lake.
2. The major sources of pollution are agricultural runoff containing residues of several agrochemicals, fertilizers, fish tank discharges, industrial effluents containing chemical residues.

v) How was the threat to the lake due to pollution discovered?
Answer:

1. The water of the lake turned alkaline in nature, turbid, nutrient rich, low in dissolved oxygen and high in biochemical oxygen demand.
2. Water borne diseases like diarrhoea, typhoid, amoebiasis and others are said to be common among the local inhabitants who are unaware of the state of pollution in the lake water.
3. Vector borne diseases were also increased.

vi) What could be the reasons for the migration of birds to this lake?
Answer:
To avoid extreme cold weather conditions in Northern Asia and Eastern Europe birds migrate to Kolleru lake.

Question 8.
Observe the following table showing different activities in the lake and their influence.
Legend:
(+) means has influence on the mentioned problem
(-) means has no influence on the mentioned problem
i) What are the factors that affected the number of migratory birds to decrease?
Answer:
Aquaculture practices.

ii) Do you find any relationship between biological and physical problems?
Answer:
Yes. Aquaculture practices have influence on these problems.

iii) What are the reasons for chemical problems ?
Answer:
Agricultural practices, aquaculture practices, industrial activities and human activities are the reasons for chemical problems.

iv) What happens if the dissolved oxygen reduce in lake water ?
Answer:
If the dissolved oxygen reduces in lake water, sufficient amount of oxygen will not be available to organisms that live in the lake.
This leads to the death of organisms in the lake.

v) Is BOD of turbid and nutrient rich water high or low? What are its consequences?
Answer:
High. Its consequences are water borne diseases and death of organisms.

vi) People living in catchment area of Kolleru faced so many problems. Why?
Answer:
Vector borne disease increased. The lands adandoned are useless for agriculture.

Question 9.
Name any two pesticides / insecticides you have heard about.
Answer:
DDT, Aldrin, Malathian, Altrazine, Monocrotophos, Endosulphan etc.

Question 10.
How are the food grains and cereals being stored in your house and how dojyou protected them from pests and fungus?
Answer:
To protect food grains and cereals from pests and fungus, we will follow the following rules in our house.

1. First of all we will dry and clean our grain before storing.
2. We will avoid moisture in bagged grains by storing them on wooden structures, bamboo mats or polythene covers.
3. We use domestic bins or improvised storage structures such as Gaade, Kotlu, Paatara, RCC bins and flat bottom metal bins etc.
4. We fumigate the storage room with Ethylene Di-bromide (EDB) ampoules to avoid insect damage.
5. We use anticoagulant for rat control in houses.

Question 11.
Where from pollutants enter to the water sources?
Answer:
The used water from industries and run off water containing agricultural effluents bring pollutants into water sources. Municipal and domestic sewage also pollute water sources.

Question 12.
How can you say fishes living in water having heavy metals in their bodies?
Answer:
The bioaccumulation of heavy metals in tissues of fish particularly in liver, kidney and gills were analysed and found their presence.

Question 13.
Researchers found that pollution levels increase during monsoon season. Why they found so?
Answer:

1. Pollution levels increase during monsoon season in water bodies.
2. During monsoon season heavy rainfall occurs.
3. The rain water brings residues of agrochemicals, fertilizers and different types of organic substances, municipal and domestic sewage.
4. Hence pollution levels increase in monsoon season.

Question 14.
Why did people also suffer from various diseases after consuming fishes living in local water reservoir?
Answer:

1. The heavy metals could find their way into human beings through food chain.
2. This bioaccumulation cause various physiological disorders such as hypertension, sporadic fever, renal damage, nausea etc.

Question 15.
What is the food chain that has been discussed in the above case?
Answer:
The food chain discussed in the above occurrence is Crops → Locust → Sparrow → Hawk.

Question 16.
How did the campaign disturb the food chain in the fields?
Answer:

1. Crop yields after the campaign were substantially decreased.
2. Though the campaign against sparrows ended it was too late.
3. With no sparrows to eat the locust populations, the country was soon swarmed.
4. Locust coupled with bad weather led to the great Chinese famine.

Question 17.
How did these disturbances affect the environment?
Answer:

1. The number of locust increased.
2. Use of pesticides against locust population further degraded the land.

Question 18.
Is it right to eradicate a living organism in an ecosystem? How is it harmful?
Answer:

1. No, it is not right to eradicate a living organism in an ecosystem.
2. It disturbs the existing food chain.

Question 19.
Were the sparrows really responsible? What was the reason for the fall in crop production?
Answer:

1. No, the sparrows were not really responsible for the loss of food grain.
2. With no sparrows to eat the locust population crops were damaged and this led to fall in crop production.

Question 20.
What was the impact of human activities on the environment?
Answer:

1. The human activities badly affected the environment.
2. Use of pesticides against the pest degraded the land.

Question 21.
What do you suggest for such incidents not to occur?
Answer:

1. I suggest to use organic manures and organic insecticides to kill the insects.
2. Rotation of crops is the best method to protect the crops from pests.
3. We should not kill any organism on this earth because every organism has a role to play.
4. Think before you start action.

10th Class Biology 9th Lesson Our Environment Activities

Activity – 1

Observe any water ecosystem in your surroundings and identify the different food chains and food web operating in this ecosystem. Write the following details in your notebook.

WORKSHEET

1. Names of the students in a group: ——————— Date: ———–
2. Name of the ecosystem: ———————
3. Topography: ———————
4. Names / Number of plants (producers) identified: ———————
5 Names / Number of animals identified: ———————
6. Identify the different types consumers and name them & mention their number below :
Herbivores (Primary consumers): ———————
Carnivores (Secondary consumers): ———————
Top carnivores (Tertiary): ———————
7 Food relationships among them: food habits/preferences: ———————
8 Show / draw the different food chains: ———————
9. Showcase the food web: ———————
10. List out all abiotic factors existing in the ecosystem: ———————
( A check list can be given, and asked to tick)
11. Is there any threat to the ecosystem ? Yes / No ———————
If yes, what ? and how ? ———————
Suggest few remedial measures ———————
Answer:
Student’s Activity.

AP State Board Syllabus AP SSC 10th Class Biology Solutions Chapter 8 Heredity Textbook Questions and Answers.

AP State Syllabus SSC 10th Class Biology Solutions 8th Lesson Heredity

10th Class Biology 8th Lesson Heredity Textbook Questions and Answers

Improve your learning

Question 1.
What are variations? How do they help organisms?
Answer:

1. Differences in characters within very closely related groups of organisms are referred to as variations.
2. Variations develop during reproduction in organisms.
3. Variations are passed from parent to offspring through heredity.
4. Beneficial variations are selected by the nature in evolution.
5. Variations increase the survival chance of the organisms.
6. These variations help the organisms to adapt to their environments.
7. For example, green colour in the beetles is a variation that gave a survival advantage to the beetles as they cannot be seen by the crows.
8. Some variations do not help organisms to survive. For example, colour variation occurs in red beetles and some blue beetles are produced instead of red beetles as they are eaten by crows easily.

Question 2.
One student (researcher) wants to cross pure tall plant (TT) with pure dwarf (tt) plant, what would be the Fj and F2 generations? Explain.
Answer:

1. Pure tall plant has both the factors of the same type ‘TT’.
2. Pure dwarf plant has both the factors of the same type ‘tt’.
3. When a pure tall plant (TT) is crossed with pure dwarf plant (tt), all the offsprings in Fj generation are tall (Tt).
4. So all the plants are heterozygous tall, as ‘T’ is the dominating factor.
   
5. On self pollination of these F₁ generation plants the new breed can have any combination of T and t like TT, Tt, Tt or tt.
   
6. So in F₂ generation 75% of plants are tall and 25% of plants are dwarf. Thus the phenotype ratio is 3 : 1.
7. Among 75% of tall plants 25% are pure tall (TT) or homozygous tall, remaining 50% are heterozygous tall (Tt, tT).
8. The remaining 25% dwarf plants are pure or homozygous dwarf (tt).
9. So the genotype ratio is 1 : 2 : 1.

Question 3.
One experimenter cut the tails of parent rats, what could be the traits in offsprings? Do the daughter rats contain tails or not? Explain your argument.
Answer:

1. If the tails of parent rats were cut, their offsprings will have normal tails.
2. Daughter rats do not contain tails because the bodily changes are not inherited.
3. So the change would not be passed to their offsprings.
4. This was proved experimentally by Augustus Weisemann and rejected the theory ‘inheritance of acquired characters’ proposed by Lamarck.

Question 4.
In a mango garden a farmer saw one mango tree with full of mango fruits but with a lot of pests. He also saw another mango tree without pests but with few mangoes. But the farmer wants the mango tree with full of mango fruits and pests free. Is it possible to create new mango tree which the farmer wants? Can you explain how it is possible?
Answer:

1. Yes, it is possible to create new mango tree which one the former wants with full of mango fruits and pests free.
2. The former can cross two plants one with full of mangoes and pests and another plant with less mango fruits and without pests,
3. In F₁ generation he may get plants with full of mango fruits and without pests. Such plants are called hybrid plants.
4. The F₁ generation plants can be self pollinated and desired plants can be selected from the mixed population of F₂ generation.
5. The plant with desirable characters can be vegetatively propagated to get required number of plants.

Question 5.
ExplaIn monohybrid experiment with an example. Which law of inheritance can we understand? Explain.
Answer:

1. We can understand the law of inheritance with an example of monohybrid cross between pure yellow pea seeds with pure green pea seeds.
2. A pure breed (parental) yellow will have both the factors which denote them by ‘YY’ and pure breed (parental) green seed will have both the factors denote them by ‘yy’.
3. During reproduction one factor (genes) from each parent is taken to form a new pair in the progeny (off spring).
4. In F₁ generation all pea plants are Yellow.
   
5. F₁ generation pea plants are self pollinated.
6. In F₂ generation 75% of the plants produced were Yellow seeds and the remaining 25% produced were green seed. It can be represented as
   
   In F₂ generation the produced plants are YY, Yy; yY or yy.
   From the above example of monohybrid cross we can understand the following laws of inheritance.

1) When pure breed Yellow (YY) and green (yy) seeds were crossed, only Yellow seeds were expressed phenotypically in the F₁ generation. It indicates that Yellow seed character is dominent over green seed characters.
This is “LAW OF DOMINANCE”.

2) When F₁ plants are self pollinated each parent passes randomly selected allele (Y or y) of one of these factor to offsprings. This is segregation of alleles or genes during production of gametes.
This is “LAW OF SEGREGATION”.

Question 6.
What is the law of independent assortment? Explain with an example.
Answer:

1. In the inheritance of more than one pair of characters (traits), the factors for each pair of characters assorts independently of the other pairs. This is known as “Law of independent assortment”.
2. If pea plants with two different pairs of characteristics (eg. : Round / yellow and green wrinkled) are breed with each other, the F₁ progeny plants would have all round and yellow seeds.
3. This implies that round and yellow seeds are dominant characters over green and wrinkled seeds.
4. In F₂ progeny there would be some plants with round and yellow seeds and some with green and wrinkled seeds.
5. However, there would be some plants with mixed characters – yellow and wrinkled seeds and green and round seeds.
6. This depicts that round/wrinkled trait and yellow / green trait are inherited independent of each other (law of independent assortment).
   The following punnet square explains this.
   
7. The different combination of characters resulted from dihybrid cross.
   a) RRYY, RRYy, RrYy, RrYY, RRYy, RrYy, RrYy, RrYY, RrYy are having round and yellow seeds.
   b) RRyy, Rryy, Rryy have round and green seeds.
   c) rrYy, rrYy, rrYY have wrinkled and yellow seeds.
   d) rryy have wrinkled and green seeds.
8. From the result, it can be concluded that the factors for each character or trait remains separate and maintain its identity in the gametes. This is known as “Law of independent assortment”.

Question 7.
How does sex determination take place in human?
(OR)
Explain sex determination in humans with the help of flow chart.
Answer:

1. Each human cell contains 23 pairs (46) of chromosomes.
2. Out of 23 pairs, 22 pairs of chromosomes are called autosomes.
3. Remaining one pair is called allosomes or sex chromosomes.
4. There are two types of sex chromosomes – one is ‘X’ and the other is ‘Y’.
5. These two chromosomes determine the sex of an individual.
6. Females have two ‘X’ chromosomes in their cells (XX).
7. Males have one ‘X’ and one ‘Y’ chromosomes in their cells (XY).
   
8. All the gametes produced by women (ovum) will be with only X chromosomes.
9. The gametes produced by man (sperm) will be of two types, one with X chromosomes and other with Y chromosomes.
10. If the sperm carries X chromosome and fertilizes with the ovum, the resultant baby will have XX condition. So the baby will be a girl.
11. If the sperm carries Y chromosome and fertilises with the ovum, the resultant baby will have XY condition. So the baby will be a boy.

Question 8.
Explain Darwin’s theory of ‘Natural selection’ with an example.
(OR)
What do you understand by the term Natural selection? Write Darwin’s theory of evolution.
Answer:

1. Darwin proposed the theory of Natural selection.
2. Nature only selects or decides which organism should survive or perish in nature.
3. The organism with useful traits will survive and the organisms having harmful traits are going to perished or eliminated from its environment.
4. For example, a group of twelve red beetles live in a bush of green leaves.
5. They will grow their population by sexual reproduction.
6. So they generate variations in their population. Let us assume crows eat the red beetles more the population of red beetles slowly reduced.
7. Crows eat these red beetles and their population slowly reduces.
8. During this time a colour variation arises by the sexual reproduction.
9. So that there appears one beetle that is green in colour instead of red.
10. Moreover this green colour beetle passes its colour to its offsprings; so that all its progeny are green.
11. Crows cannot see the green coloured beetles on green leaves of the bushes and therefore crows cannot eat them.
12. The crows can see the red beetles and eat them as a result, there are more and more green beetles than red ones which decrease in their number.
13. The variation of green colour beetle gave a survival advantage to green beetles’ than red beetles. They were naturally selected.

Question 9.
What are variations? Explain with a suitable example.
Answer:

1. Differences in characters within very closely related groups of organisms are referred to as variations.
2. Often a new character in a group may lead to variations that are inherited.
3. If we observe parents and offsprings, there will be some similar features in the offspring of the parents.
4. At the same time we find differences between parents and offspring in their features.
5. These differences are an example of variations.
6. Variations are quite apparent among closely related groups of organisms.
7. If we take roses as an another example, we observe number of varieties in them.
8. But we can still find some characters similar to all plants.
9. Thus rose plants have similar physical features, at the same time they have differences in characters like flower colour, number of petals, leaf size, stem, spines, etc.
10. These differences in features are variations.

Question 10.
What variations generally have you observed in the species of cow?
Answer:
In the species of cow the following contrasting variations can be observed:

1. White coloured – spotted
2. Longhorns – short horns
3. Height – dwarf
4. Long-tail – short tail
5. Elongated face – stunted face
6. More milk giving – less milk giving, etc.

Question 11.
What are the characters that Mendel selected for his experiments on pea plants
(OR)
Write the seven pairs of contrasting characters in pea plant identified by Mendel and mention their traits.
Answer:
Mendel selected the following characters on pea plants for his experiment. They are:

Character	Description
1. Colour of the flower	1. Purple or white.
2. Position of the flower	2. Axial or terminal in position
3. Colour of the seed	3. Either yellow or green.
4. Shape of the seed	4. Either round or wrinkled.
5. Shape of the pod	5. Inflated and constricted
6. Colour of the pod	6. Yellow or green.
7. Length of the stem	7. Tall and dwarf.

Question 12.
In what way Mendel used the word ‘Traits’? Explain with an example.
Answer:

1. Trait is a separate variant of an organism.
2. Mendel hypothesized that characters were carried as traits.
3. An organism always carried a pair of factors for a character.
4. He also hypothesized that distinguishing traits of the same character were present in the population of an organism.
5. He assumed that the traits shown by the pea plants must be in the seeds that produce them.
6. The seeds must have obtained these traits from the parent plants.
7. The factors which are responsible for the character or trait of an organism, are now named as “genes”.
8. By all these we can assume that Mendel used the word ‘traits’ for indicating the variant of an organism expressed by a pair of factors or genes.
9. For example, height is a character of pea plant while the tallness is a trait expressed by a pair of factors either TT or Tt and dwarfness is another trait expressed by a pair of factors tt.

Question 13.
What are the differences that Mendel observed between parent and F₂ generation?
Answer:
Mendel identified the following differences between parent and F₂ generation.

Parent	F2 Generation
1. They are pure breeds.	1. They consist of mixed population.
2. They consist of homozygous alleles.	2. They consist of homozygous alleles in some plants and heterozygous alleles in some other plants.
3. They have some fixed characteristic features.	3. New combination of characters will appear.

Question 14.
Male is responsible for sex determination of baby – do you agree? If so write your answer with a flow chart.
Answer:

1. Yes, I agree with the statement that male is responsible for sex determination of baby.
2. There are two types of sex chromosomes in human beings, one is ‘X’ and other is ‘Y’.
   
3. Females have two ‘X’ chromosomes in their cells (XX) whereas males have one ‘X’ and one ‘Y’ chromosomes in their cells (XY).
4. All the gametes produced by woman (ovum) will be with only X chromosomes.
5. The gametes produced by man (sperm) will be of two types one with X chromosomes and other Y chromosomes.
6. If the sperm carrying X chromosome fertilizes the ovum, the resultant baby will have XX condition. So the baby will be a girl.
7. If the sperm carrying Y chromosome fertilizes the ovum, the resultant baby will have XY condition. So the baby will be a boy.
8. So the gamete produced by the male is the deciding factor for sex determination of the baby.

Question 15.
Write a brief note on analogous organs.
(OR)
What are analogous organs?
Answer:

1. The organs which are structurally different but functionally similar are known as ‘Analogous organs’.
2. Wings of birds and bats is the example for analogous organs.
3. The wings of bats are skin folds stretched mainly between elongated fingers.
4. But the wings of birds are a feathery covering all along the arm.
5. The designs of the two wings, their structure and components are different.
6. They look similar because they have common use for flying, but their origins are not common.
7. This makes the ‘analogous’ characteristics.
8. This type of evolution is called convergent evolution.

Question 16.
How do scientists utilise information about fossils?
(OR)
“Fossils are valuable material that nature had preserved to know about ancient organisms.” Write the information you have collected about fossils.
Answer:

1. Fossils are evidence of ancient life forms or ancient habitats which have been preserved by natural processes.
2. The scientific study of fossils is called ‘Palaeontology’.
3. Scientists utilise information about fossils to understand the evolutionary history of life.
4. This information is also useful to study ecology and environmental history, such as ancient climates.
5. This also helps to find out how old that certain layer of earth is.
6. This information is also utilized as indicators of possible fossil fuel deposits which are of great interest to humanity.
7. Thus scientists utilize the information on fossils to learn more about the earth’s past.

Question 17.
Mendel selected a pea plant for his experiments. Mention the reasons for the selection as these plants.
(OR)
Why did Mendel select the pea plant for his experiment? (OR)
Which characters in the pea plant are selected by Mendel, for his experiments?
What are the reasons for selecting pea plant by Mendel to conduct his experiments?
Answer:
Mendel chose the pea plant (Pisum sativam) for his breeding experiments for the following reasons.

1. It is sexually reproducing.
2. Flowers are bisexual.
3. Predominantly self-pollinated.
4. Predominantly self-fertilization.
5. Well developed characters.
6. Early hybridization.
7. It is an annual plant.
8. These plants have short maturity and can produce large number of seeds in a single generation.
9. Pea plants have short life cycle.
10. These plants can easy to grow either on the ground or in pots.

Question 18.
If the theory of inheritance of acquired characters proposed by Lamarck was true, how will the world be?
Answer:
If the theory of inheritance of acquired characters proposed by Lamarck was correct,

1. All the organisms which lost some of their body parts should give birth to the offsprings without the lost parts.
2. Rat which lost their tail should give birth to tail less rats.
3. A handicapped who lost their legs in an accident should give birth to babies v without legs.
4. A body builder’s children should be body builders.
5. But all these are not happening because bodily changes won’t be passed to its offspring.

Question 19.
Collect information on the inherited traits in your family members and write a note on it.
Answer:

1. My grandfather and father- had curling hair. I too have curling hair. So it’s an inherited trait in family.
2. My mother and I both have long noses which appear similar. It’s another inherited trait.
3. Eyes of my grandmother, my brother and mine are similar. It’s another inherited trait.
4. Ear lobes of my father, brother and mine are similar. This is another inherited trait.

Question 20.
With the help of given information write your comment on evidences of evolution.

Mammals have fore limbs as do birds, reptiles and amphibians. The basic structure of the limbs is similar, though it has been modified to perform different functions.

Answer:

1. The given information gives the evidences of evolution.
2. Mammals. birds, reptiles and amphibians all these have forelimbs which have similar basic structure.
3. But they are modified to perform different functions.
4. This indicates that all the vertebrates have evolved from a common ancestor. These organs are called homologous organs. This type of evolution is called divergent evolution.
5. In case of bat (mammal) and bird the designs of the two wings, their structure and components are different.
6. They look similar because they have common use for flying, but their origins are not common.
7. These organs which are structurally different but functionally similar are known as ‘Analogous organs’. This type of evolution is called “convergent evolution”.
8. There are remarkable similarities in the embryos of above mentioned animals even in their limb formation. These are called embryological evidences.

Question 21.
Collect information about carbon dating method. Discuss with your physical science teacher.
(OR)
Write about the carbon dating method from the information collected by you.
Answer:

1. Carbon dating is the method used to calculate the age of rocks, minerals or fossils.
2. The breakdown of radioactive isotopes of certain elements such as carbon, uranium and potassium takes place at a known rate. So the age of rock or mineral containing isotopes can be calculated.
3. Archaeologists use the exponential, radioactive decay of carbon 14 to estimate the death dates of organic material.
4. The earth’s atmosphere contains various isotopes of carbon, roughly in constant proportions.
5. These include the main stable isotope ¹²C and an unstable istope ¹⁴C.
6. Through photosynthesis, plants absorb both forms from carbon dioxide in the atmosphere.
7. When an organism dies, it contains the standard ratio of ¹⁴C to ¹²C.
8. But as the ¹⁴C decays with no possibility of replenishment, the proportion of carbon 14 decreases at a known constant rate.
9. The time taken for it to reduce by half is known as the half-life of ¹⁴C, which is 5730.
10. The measurement of the remaining proportion of ¹⁴C in organic matter thus an estimation of its age.
11. As the half life of carbon – 14 is 5,700 years, it is useful for dating objects up (o about 60,000 years old.

Question 22.
Draw a checker board, show the law of independent assortment with a flowchart and explain the ratio.
Answer:

1. The phenotypic ratio is 9 : 3 : 3 : 1. i.e., 9 round and yellow seeds 3 round and green seeds, 3 wrinkled and green seeds and 1 wrinkled and green seed.
2. RRYY, RRYy, RrYy, RrYy, RRYy, RrYy, RrYy, RrYY and RrYy are round and yellow seeds.
3. RRyy, Rryy, Rryy are round and green.
4. rrYY, rrYy, rrYy are wrinkled and yellow.
5. rryy are wrinkled and green.

From the above result, it can be concluded that factors for each character or trait remains separate and maintains its identity in the gametes. Thus in the inheritance of more than one pair of characters, the factors for each pair of characters assort independently of the other pairs. This is known as “Law of independent assortment”.

Question 23.
Explain the process to understand the monohybrid cross of Mendel experiment with a checker board.
Answer:

Question 24.
Prepare a chart showing the evolution of man through ages.
Answer:

Question 25.
Nature selects only desirable characters. Prepare a cartoon.
Answer:
Nature selects only desirable characters

Question 26.
What is your understanding about survival of the fittest? Give some situations or examples that you observe in your surroundings.
Answer:

1. Nature favours only useful variations.
2. Each species tends to produce a large number of offspring.
3. They compete with each other for food, space, mating and other species.
4. In this struggle for existence only the fittest can survive.
5. When cat tries to catch some rats, the rats which can run fast and hide in its hole can survive and which is slow can become prey for the cat.
6. When we spray some insecticide on insects, most of them will die but few which can withstand that chemical will escape.
7. When a pest attacks our garden plants, most of them may die but Which can withstand the pest can survive.
8. When the dog tries to catch chickens, the chickens which will run fast and escape can survive but the slower ones will become food for the dog.

Question 27.
Write a monologue on the evolution of a human to perform a stage show on the theatre day in your school.
Answer:

1. Hai, I am a human being. I am going to recall what had happened to me so far, how I had evolved, simply my journey from my origin to till now.
2. Nearly 1.6 – 2.5 million years ago, during the gelasian pleistocene period, I used to wander in the forest. It is belived that, I evolved from apes.
3. Between 1-1.8 million years ago, I gradually evolved into Homo erectus. I lived in this stage throughout most of the pleistocene. I used more diverse and sophisticated stone tools than my predecessors and it is belived that I travelled over oceans using rafts.
4. Around 1,00,000 – 40,000 thousand years ago I evolved into Homo sapiens neanderthalensis. I was stronger than present in those days. I made advanced tools. I had language to communicate.
5. Around 40 thousand years ago, I reached the present form of human being, the modern humans known as Homo sapiens. I learnt cultivation, construction of houses, cooking, etc. I had invented various things that help me to live comfortably.
6. But my journey did not stop. It is still continuing. Let us see what may happen? Where can I reach? What changes may come in me? Hope for the best.
   Thank you.

Fill in the blanks.

1. The process of acquiring change is called ———–.
2. Mendel’s experiment explains about ———–.
3. The four characters observed in the experiments on law of independent assortment are ———–.
4. If we cross pollinate red flower plant with white flower we will get percent of ———– recessive trait plants.
5. TT or YY, Tt or Yy are responsible for a ———– character.
6. Female baby having 23 pairs of autosomes at the age of 18 years, has ———– pair autosomes and ———– of sex chromosomes.
7. The population grows in ———– progression whereas food sources grow in ———– progression.
8. A goat which walks properly can’t live for a long time. According to Darwin, this represents ———–.
9. Forelimb of whale is for swimming whereas in horse it is used for ———–.
10. The study of fossils is called ———–.

Answer:

1. evolution
2. heredity
3. Round, wrinkled, yellow, green
4. 100
5. dominant
6. 22, one pair
7. geometrical, arithmetic
8. survival of the fittest
9. running
10. palaeontology

Choose the correct answer.

1. Which of the following is not a variation in rose plant?  [ ]
   A) Coloured petals
   B) Spines
   C) Tendrils
   D) Leaf margin
   Answer: C
2. According to Mendel, alleles are  [ ]
   A) Pair of genes , Responsible for character
   B) gene
   C) Production of Gametes
   D) Recessive factors
   Answer: B
3. Natural selection means  [ ]
   A) Nature selects desirable characters
   B) Nature rejects undesirable characters
   C) Nature reacts with an organism
   D) A, B
   Answer: A
4. Palaeontologists deal with  [ ]
   A) Fossilised Embryological evidences
   B) Fossil evidences
   C) Fossilised Vestigial organ evidences
   D) All
   Answer: D

10th Class Biology 8th Lesson Heredity InText Questions and Answers

10th Class Biology Textbook Page No. 166

Question 1.
How does evolution take place?
Answer:

1. Evolution takes place through the accumulation of new characters or variations in a species of organisms.
2. Accumulation of variations occurs only when new characters are passed on from one generation to other and much more new characters are added to the pre-existing once.
3. So this happens oVer a kirig period of time, sometimes several generations may pass.
4. Hence it happens in a slow and steady manner.
5. It is not just about change but producing something new and different.
6. It is about the formation of new species and their adaptation to their environments.

10th Class Biology Textbook Page No. 168

Question 2.
Is variation all about apparent differences? Or is it about some subtle differences as well that we most often overlook?
Answer:

1. Variations are not always apparent differences.
2. Sometimes these may be subtle differences that we most often overlook.
3. When these subtle differences accumulate together they may become apparent.

10th Class Biology Textbook Page No. 171

Question 3.
How do parent plants pass on their traits to the seeds?
Answer:

1. Every character or trait is controlled by a pair of factors called genes.
2. At the time of sexual reproduction, one factor or each trait will pass to the gametes.
3. By the fussion of male and female gametes zygote will form in which factors from both male and female parents get paired again.
4. This zygote will develop into seed in the later stages.
5. Thus parent plants pass on their traits to the seeds.

Question 4.
Will the seeds from tall plants always produce new tall plants?
Answer:

1. No. Tall plants may or may not produce tall plants again.
2. This is because tallness is a dominant character in most of the plants, especially in peas.
3. So tall plant may be homozygous tall (TT) or heterozygous tall (Tt).
4. If the parental plant is homozygous tall (pure breed), then they always produce new tall plants.
5. If the parental plant is a heterozygous tall plant, then they produce the tall and dwarf plants in the ratio of 3 : 1.

10th Class Biology Textbook Page No. 175

Question 5.
What should be the percentage of each type of plants in F₂ generation produced in dihybrid cross between pea plants with yellow, smooth seeds and green wrinkled seeds?
Answer:

1. In F₂ generation of dihybrid cross between pea plants with yellow, smooth seeds and green wrinkled seeds, new plants will produce with the following combination.
   i) Round and yellow
   ii) Round and green and
   iii) Wrinkled and green iv) Wrinkled and yellow
2. They will produce in the ratio of 9 : 3 : 3 : 1 respectively.
3. So 56 (56.25%) of plants should be with round and yellow seeds. 19 (18.75%) of plants should be with wrinkled and yellow seeds. 19 (18.75 %) of plants should be with round and green seeds and 6% (6. 25%) of plants should be with wrinkled and green seeds.

10th Class Biology Textbook Page No. 178

Question 6.
What will happen if the sperm containing X chromosomes fertilizes the ovum?
Answer:

1. If the sperm containing X chromosomes fertilizes the ovum which has X chromosome, the baby will have XX condition.
2. So the baby will be a girl.

Question 7.
Who decides the sex of the baby – mother or father?
Answer:
Father decides the sex of the baby.

Question 8.
Is the sex also a character or trait? Does It follow Mendels’ law of dominance?
Answer:

1. Yes, sex is also a character or a trait.
2. It has two contrasting characters male and female.
3. Male character is represented by a pair of allosomes ‘XY‘ (heterozygous).
4. In this, we can consider Y as dominant and X as recessive.
5. In this, recessive character is expressed only when it is homozygous recessive, i.e. female.
6. Homozygous dominant is not existing as reproduction occurs between male (heterozygous dominent XY) and female (homozygous recessive XX) only.
7. As X is not exhibiting its nature when Y is present along with it. it follows Mendel’s law of dominance.

Question 9.
Were all your traits similar to that of your parents?
Answer:

1. No, all my traits are not similar to my parents.
2. There are certain traits which differ from my parents.

10th Class Biology Textbook Page No. 185

Question 10.
How does the evolution of organisms have taken place?
Answer:

1. Variations which are beneficial are selected by nature and passed from parents to offspring through heredity.
2. The same process happens with every new generation until the variation becomes common feature.
3. As the environment changes, the organism within environment adopts and changes to the new living conditions.
4. Over a long period of time, each species of organisms can acuumulate so many changes that it becomes a new species.
5. Thus evolution of organisms took place from common pre-existing ancestors.

Question 11.
Are birds and bats more closely related to each other than to squirrels or lizards?
Answer:

1. No, bats are mammals whereas birds belong to aves.
2. Squirrels are mammals and lizards belong to reptiles.
3. So bats and birds are not closely related to each other as they belong to two different groups.
4. Both bats and birds have wings.

10th Class Biology Textbook Page No. 186

Question 12.
Do embryological evidences indicate that frogs have evolved from ancestors of fish?
Answer:
Yes the embryological evidences indicate that frogs have evolved from ancestors of fish.

Question 13.
Does the life history of every individual exhibit the structural features of their ancestors?
Answer:

1. Yes. The life history of every individual exhibit the structural features of its ancestors.
2. The resemblance is so close at an early stage.

10th Class Biology Textbook Page No. 189

Question 14.
Think why did ancient human beings travelled from one place to other and how did they travelled?
Answer:

1. Ancient human beings travelled from one place to other in search of better living conditions such as availability of food, water shelter and other facilities.
2. They did not travel in a single line.
3. They went forwards and backwards with groups, sometimes separating from each other.
4. This travel is responsible for the formation of races.

10th Class Biology Textbook Page No. 183

Question 15.
In a forest there are two types of deer, in which one type of deer can run very fast. Whereas second type of deer can not run as fast as the first one. Lions, Tigers hunt deer for their food. Imagine which type of deer are going to survive in the forest and which type of deer population is going to be eliminated? And why?
Answer:

1. Deer that can run fast can survive in the forest. Because they can escape easily from lions and tigers, when compared to second type.
2. Deer that run slowly are going to be eliminated. Because they can be caught easily by its predators. So the survival chance will decrease.

10th Class Biology 8th Lesson Heredity Activities

Activity – 1

Think of your own family, what similarities do you share with your father and mother? Draw a table to represent the similarities of some characters like colour of eye (cornea), colour of hair, shape of nose, shape of face, type of earlobe (attached or free), inner thumb markings, etc. Write your characters in one column and that of your parents in the other columns.
Table – 1

Characters	In me	In my Mother/Father	In my Brother/Sister	In my grandma/grandpa

Answer:

S.No.	Characters	In me	In my Mother/Father	In my Brother/Sister	In my grandma/grandpa
1.	Colour of eye	Black	Black	Black	Black
2.	Colour of hair	Black	Black	Black	Black
3.	Shape of nose	Long	Long	Short	Short
4.	Shape of face	Oval	Round	Oval	Oval
5.	Type of earlobe	Free	Free	Free	Free
6.	Type of hair	Curling	Curling	Straight	Straight
7.	Inner thumb marking	Conical	Round	Round	Conical
8.	Skin colour	Fair	Fair	Fair	Fair

1. Is there any character in you similar to that of your mother as well as your grandma?
Answer:
There are four characters in me similar to my mother as well as my grandma. They are

1. Colour of eye
2. Colour of hair
3. Type of earlobe and
4. Skin colour.

2. Is there any character in you similar only to that of your grandma?
Answer:
Two characters are similar in me and in my grandma. They are

1. Shape of face and
2. Inner thumb marking.

3. How do you think these characters may have been inherited by you from grandma?
Answer:
These characters are hereditary from parent to child.

4. Is there any character that is not present in grandma but present in your mother and you?
Answer:
Two characters are not present in grandma which are only present in me and my mother. They are

1. Shape of nose
2. Type of hair

5. Think where from your mother got that character?
Answer:
This character is the result of inherited traits transmitted from parent to progeny.

Activity – 2
Observe some of your friends and note their characters in the following table. Fill in yours as well.
Table – 2

Name of your friend	Colour of skin	Earlobes Free / Attached	Marking on inner side of thumb	Length of forehead	Colour of eyes (Cornea)	Any other features

Answer:

Name of your friend	Colour of skin	Earlobes Free / Attached	Marking on inner side of thumb	Length of forehead	Colour of eyes (Cornea)	Any other features
Ravi	Black	Free	Round	Broad	Blue	Straight hair, long nose, and face, etc.
Ganesh	Black	Attached	Conical	Narrow	Black	Straight hair, short nose, oval face, etc.
Vi jay	Fair	Free	Conical	Broad	Black	Curling hair, short nose, round face, etc.
Karthik	Fair	Free	Round	Broad	Black	Straight hair, long nose, round face, etc.

1. Compare your characters to that of any one of your friend. How many characters did you find were similar among you and your friend?
Answer:
Only few characters such as black hair and black eye were similar among me and my friend.

2. Do you share more similar characters with your parents or with your friends?
Answer:
I share more similar characters with my parents than my friends.

3. Do you think that your differences from parents are same as differences from friends? Why / Why not?
Answer:
My differences from parents are not same as differences from friend. This is because the differences from parents are subtle as there is more genetic relation with parents but the differences from friends are apparent.

Activity – 3

Observe seeds in a pea or bean pod. You may observe several parts to arrive at a generalisation.

1. Can you find two similar seeds there?
Answer:
No, all the seeds are not similar. They had certain variations.

2. What makes them vary? even though they are in the same pod. (Hint: You know that seeds are formed from ovules).
Answer:

1. They vary from one another because they are produced from different ovules.
2. Ovules of a plant are female gametes.
3. These gametes carry different factors (genes) for different characters randomly.

3. Why variations are important? How are variations useful for an organism or a population?
Answer:

1. Variations perhaps help a certain group of organisms in a community when conditions would otherwise be unfavourable for other groups.
2. Desirable variations can be selected by nature.
3. Desirable variations increase the chance of survival of an organism.
4. Accumulation of variations after a long period leads to formation of new species.

Activity – 4

Let us do the following activity to understand the Mendelian principles of Heredity. Materials required :
a) 3 cm length and 1cm breadth chart pieces – 4
b) 2 cm length and 1cm breadth chart pieces – 4
c) Red buttons – 4
d) White buttons – 4
e) Chart, scale, sketch pen, pencil, 2 bags.

Method: Prepare a chart with 2×2 boxes along with number and symbol as shown in the figure.

Game 1: Monohybrid cross (starting with hybrid parents)
To start with take 1, 2 or 3, 4 . In case you start 1, 2 pick all the 16 long and short pieces and prepare such pairs in each of which you have a long and short piece.

Take 4 pairs each of long and short strips and put them in two separate bags. Now each bag contains 8 strips (4 long and 4 short).One bag say ‘A’ represents male and the bag ‘B’ represents female. Now randomly pick one strip each from bag A and B and put them together in the 1 on the chart. Keep picking out the strips and arrange them in the same manner till your bags are empty. Same time your boxes in the chart are filled with pairs of strips. You might have got the following combinations, two long strips, one long and one short strip, two short strips.

1. What is the number of long strip pairs?
Answer:
There are four long strip pairs.

2. What is the number of one long and one short pairs?
Answer:
There are eight, one long and one short strip pairs.

3. What is the number of short strips pairs?
Answer:
There are four short strip pairs.

4. What is the percentage of each type? Also find their ratios.
Answer:
The percentage of long strip pairs, one long and one short strip pairs and short strip pairs are 25%, 50% and 25% respectively and the ratio is 1 : 2 : 1.

5. What can you conclude from this game?
Answer:
From this game I have concluded that:

1. Every individual possesses a pair of alleles, for any particular trait.
2. Each parent passes a randomly selected copy (allele) of these to an offspring.
3. The offspring then receives its own pair of alleles for that trait one each from both parents.
4. If the long strip is considered as dominant 75% exhibit dominant and 25% exhibit recessive character. Thus the phenotype ratio is 3 : 1 in monohybrid cross.
5. The genotype ratio is 1 : 2 : 1.

Activity – 5

Observe the below diagram showing variation in beetle population and its impact.
Let us consider a group of twelve beetles. They live in bushes on green leaves. Their population will grow by sexual reproduction. So they were able to generate variations in population. Let us assume crows eat these red beetles. If the crows eat more Red beetles, their population is slowly reduced. Let us discuss the above three different situations in detail.
Answer:
Situation-1: In this situation, a colour variation arises during reproduction. So that there appears one beetle that is green in colour instead of red.
Moreover, this green coloured beetle passes its colour to Its offspring (Progeny). So that all its progeny are green. Crows cannot see the green coloured beetles on green leaves of the bushes and therefore crows cannot eat them. But crows can see the red beetles and eat them. As a result there are more and more green beetles than red ones which decrease in their number.

The variation of colour in beetle ‘green’ gave a survival advantage to’green beetles’ than red beetles. In other words it was naturally selected. We can see that the ‘natural selection’ was exerted by the crows. The more crows there are, the more red beetles would be eaten and the more number of green beetles in the population would be. Thus the natural selection is directing evolution in the beetle population. It results in adaptation in the beetle population to fit in their environment better.

Let us think of another situation.
Situation-2: In this situation a colour variation occurs again in its progeny during reproduction, but now it results in ‘blue’ colour beetles instead of ‘red’colour beetle. This blue colour beetled can pass its colour to its progeny. So that all its progeny are blue.
Crows can see blue coloured beetles on the green leaves of the bushes and the red ones as well. And therefore crows can eat both red and blue coloured beetles. In this case there is no survival advantage for blue coloured beetles as we have seen in case of green coloured beetles.

What happens initially in the population, there are a few blue beetles,but most are red. Imagine at this point an elephant comes by and stamps on the bushes where the beetles live. This kills most of the beetles. By chance the few beetles survived are mostly blue. Again the beetle population slowly increases. But in the beetle population most of them are in blue colour.

Thus sometimes accidents may also result in changes in certain characters of the population. Characters as we know are governed by genes. Thus there is change in the frequency of genes in small populations. This is known as “Genetic drift’, which provides diversity in the population.

Let us think of another situation :
Situation-3: In this case beetles population is increasing, but suddenly bushes were affected by a plant disease in which leaf material were destroyed or in which leaves are affected by this beetles got less food material.
So beetles are poorly nourished. So the weight of beetles decrease but no changes take place in their genetic material (DNA). After a few years the plant disease are eliminated. Bushes are healthy with plenty of leaves.

What do you think will be condition of the beetles?
Answer:
The weight of beetles will increase once again as they get plenty of food material again.

Activity – 6

Let us observe different stages of development of vertebrate embryos. Try to find out similarities and differences and discuss with your friends.
(OR)
What do you infer about the embroyological evidences of various organisms?
Answer:

1. There are remarkable similarities in the embryos of different animals from fish to man.
2. The resemblance is so close at an early stage.
3. Gradually the similarities are decreased when they become babies.
4. The embryological evidences give us an idea that all the organisms have evolved from a common ancestors.

 

AP State Board Syllabus AP SSC 10th Class Biology Solutions Chapter 7 Coordination in Life Processes Textbook Questions and Answers.

AP State Syllabus SSC 10th Class Biology Solutions 7th Lesson Coordination in Life Processes

10th Class Biology 7th Lesson Coordination in Life Processes Textbook Questions and Answers

Improve your learning

Question 1.
What do you mean by hunger pangs?
Answer:

1. When glucose levels in the blood fall, hunger pangs occur in the stomach.
2. Ghrelin hormone is secreted in the stomach when it goes empty.
3. Ghrelin is secreted from certain cell walls of the stomach.
4. Hunger contractions (hunger pangs) start to occur in the stomach due to secretion of ghrelin hormone.
5. Hunger pangs continue up to 30 – 45 minutes.
6. An increase in Ghrelin levels results in sensation of hunger and motivation to consume food.

Question 2.
What are the organ systems involved in the digestion of food which we eat?
Answer:
The organ systems involved in the digestion of food are:

1. endocrine system,
2. nervous system,
3. muscular system,
4. circulatory system and
5. excretory system.

Question 3.
Rafi said smell also increases our appetite. Can you support this statement ? How?
Answer:

1. Yes. I support the statement made by Rafi that smell also increases our appetite.
2. When we smell, the air borne substances get dissolved in the watery film of nasal mucus.
3. The chemoreceptors which are otherwise called olfactory receptors present in the nose trigger signals in the form of nerve impulses to the brain where the smell is detected.
4. However interactions between the senses of taste and smell enhance our appetite.

Question 4.
Write a note on peristalsis and sphincter function in the stomach.
Answer:
A) Peristalsis functions in stomach:

1. Contraction and relaxation of the muscles present in the stomach bring in a wave-like motion called peristalsis.
2. The contraction of the stomach muscles squeeze and mix the food with the acids and juices of the stomach.
3. Mechanical mixing of food in stomach occurs by peristalsis. This allows the mass of food to further mix with the digestive enzymes.
4. Peristalsis in stomach is involuntary and under the control of the autonomous nervous system.

B) Sphincter functions in the stomach:

1. Pyloric sphincter is present at the opening of the stomach into the duodenum (small intestine).
2. The pyloric sphincter allows only small quantities of food into duodenum at a time.

Question 5.
Observe the given part of the digestive system. What is it ? What is it’s role during digestion ?
Answer:

1. The given part is the LARGE INTESTINE in the human digestive system:
   
2. If creates peristaltic waves to send waste material called stool or faeces into the rectum.
3. In the large intestine water and mineral salts are absorbed from the waste material.
4. The faecal matter containing indigested food material, bile pigments and dead bacteria is formed in the large intestine.
5. It is stored in the rectum and expelled out of the body through the Anus.

Question 6.
Give reasons.
a) If we press the tongue against the palate, we can recognize taste easily.
Answer:
Reason :

1. When the tongue is pressed against the palate, the food substance is pressed against the opening of the taste bud letting it to reach the taste cells and triggering taste signals.
2. Finally, the taste is recognized in the brain.

b) We can’t identify taste when food is very hot.
Answer:
Reason:

1. Most of the taste buds on the tongue are killed when the food is hot.
2. This prevents the person from identifying the taste.
3. The perception of taste decreases when the temperature of the food rises beyond 35°C.
4. But we don’t pay attention to it because we become worried about the burning feeling.

c) If glucose level falls in blood, we feel hungry. (OR) €EI June 2015
We feel hungry if the blood glucose level falls down. 03 June 2019
Answer:
Reason :

1. When glucose levels in the blood fall, we get hunger pangs in stomach.
2. Hungry feeling start to occur in the stomach due to hunger generating signals that the brain from the stomach due to the secretion of the hormone ‘Ghrelin’.

d) Small intestine is similar to a coiled pipe. (OR)
Why is the small intestine long and coiled?
Answer:
Reason :

1. The length of small intestine is 7 meters long.
2. It is coiled so as to fit in the human body.
3. It is coiled to increase surface area and maximum nutrient absorption when food passes through it.

e) Urination increases when we take lot of fluids.
Answer:
Reason:

1. When we take lot of fluids, the kidneys will efficiently throw the water out by forming more urine than usual.
2. When there is excess water in the body, the brain usually produces less of a hormone called vasopressin.
3. This in turn causes the kidneys to produce a lot of dilute urine, until excess water is removed.

f) The process of digestion goes on in a person whose central nervous system has been largerly affected.
Answer:
Reason :

1. The enteric nervous system embedded in the walls of the long tube of our gut or alimentary canal control gut functions often independently of the brain.
2. The mass of neural tissue of enteric nervous system filled with important neurotransmitters reveals that it does much more than merely handle digestion.

Question 7.
Write differences between the following:
a) Bolus – Chyme
b) Small intestine – Large intestine
c) Mastication – Rumination
d) Propulsion – Retropulsion
Answer:
a) Bolus – Chyme:

Bolus	Chyme
1. Food that is masticated in the mouth.	1. It is the partially digested food in the stomach.
2. Alkaline in nature.	2. Acidic in nature.
3. Teeth and saliva turn food into bolus.	3. Stomach turn food by peristalsis into chyme.
4. Soft round ball of food that has been chewed.	4. It is the liquified part of food.
5. Food goes from mouth to stomach.	5. Food goes from stomach to small intestine.

b) Small intestine – Large intestine:

Small intestine	Large intestine
1. It is longer and has small width.	1. It is shorter and has broad width.
2. It is in between the stomach and large intestine.	2. It is the last part of the digestive system.
3. Digestive juices release from liver, pancreas.	3. Digestive juices are not released into large intestine.
4. Food is completely digested in it.	4. Absorption of water from the undigested food takes place in it.
5. It has three parts – duodenum, jejunum and ileum.	5. It has four parts – caecum, colon, rectum and anal canal.
6. Villi helps in absorption of digested food.	6. Villi are absent in large intestine.

c) Mastication – Rumination:

Mastication	Rumination
1. Grinding, chewing and shredding of food in the mouth by teeth is called mastication.	1. It is the chewing of cud that come from a part near the stomach of the animal to its mouth.
2. Mastication occurs only one time in the oral cavity.	2. Rumination allows food to undergo mastication more than once.
3. This is also known as chewing the food.	3. This is also known as chewing the cud.
4. It makes the food particles to tiny particles. Does not involve nutrient absorption.	4. It allows greater nutrients to be extracted and absorbed from the food particles.
5. It occurs in most of the animals (mammals), eg: Human being	5. It occurs only in ruminate animals. eg: Cow

d) Propulsion – Retropulsion:

Propulsion	Retropulsion
1. It is a means of creating force leading to movement of food.	1. It is a situation in which something (food) is pushed or forced backwards.
2. Peristaltic waves move food from one part to the other.	2. Small amount of chyme is pushed into duodenum, simultaneously forcing most of it back into the stomach.

Question 8.
How can you say that mouth is a munching machine?
Answer:

1. Mouth plays a major role in changing the texture of food.
2. The circular muscles of the mouth enable the food to be pushed into the oral cavity and to be moved around.
3. The teeth grind, chew and shred the food.
4. The surface muscles of the jaw help in biting and chewing actions, while the deep muscles of the jaw move up, down, forward and backward during food mastication.
5. The teeth help in cutting and grinding while tongue movements evenly spread out the food and help in mixing it with saliva.
6. The muscles of the mouth enable the food to be pushed in the oral cavity and to be moved around.
7. By all this we can say that mouth is a munching machine.

Question 9.
What is mastication? Explain the role of different sets of teeth in this process.
Answer:
Mastication: Food can not be swallowed directly. So it must be grinded, chewed and shred. This process of grinding, chewing and shredding is called ’MASTICATION’.
Role of different sets of teeth in mastication:

1. In the oral cavity of human beings, 32 teeth and they are 4 different types to perform different functions.
2. They are a) Inscisors b) Canines c) Premolars d) Molars
   a) Inscisors: These are eight in number and have chisel shape. They have sharp edges and are specialized for cutting and biting the food.
   b) Canines: These are four in number and are with pointed edges- These are designed for piercing and tearing food.
   c) Premolars: These are eight in number and are also called cheek teeth. These are designed for crushing and grinding food.
   d) Molars: These are 12 in number. They are designed for crushing and grinding food.

Question 10.
During the journey of food from the mouth to stomach through oesophagus, how does muscular system coordinate in this process?
Answer:
Movement of food (bolus) from mouth to stomach through oesophagus is influenced by the coordination between muscular system and nervous system.
Muscular movement in mouth:

1. The circular muscles of the mouth enable the food to be pushed into the oral cavity and to be moved around.
2. The surface muscles of the jaw help in biting and chewing actions while the deep muscles move the jaw up and down, forward and backward during mastication.

Muscular movement in oesophagus:

1. The wall of the oesophagus is made up of two kinds of smooth muscles.
2. The inner layer consists of circular muscles and the outer layer is of longitudinal muscles.
3. Contraction of circular muscles lead to narrowing of the oesophagus behind the bolus. So the food is squeezed downwards.
4. Contraction of the longitudinal muscles in front of the bolus widens the tube, results in shortening of particular part of oesophagus.
5. In this way food moves easily and enters the stomach. ,
6. Contraction and relaxation of oesophagus muscles bring peristaltic movements.

Question 11.
Is there any reason for the intestine to be coiled with many folds ? In what way it is helpful during the process of digestion? (OR)
Small intestine is similar to a coiled pipe. Give reason.
Answer:

1. Yes, there is a reason for the intestine to be coiled with many folds.
2. The coiled and folded nature of intestine slows down the passage of food along the intestine and afford an increased surface area for absorption.
3. It also increases the surface area for the intestine to increase the absorption of nutrients through finger-like projections villi.
4. The folded and coiled intestine absorbs nutrients and water more than they breakdown.

Question 12.
What is the function of peristalsis in these parts?
a) Oesophagus b) Stomach c) Small intestine d) Large intestine
Answer:
a) Oesophagus:
Peristalsis helps in pushing the food, down the oesophagus into the stomach.

b) Stomach:

1. Peristalsis helps in storing food, breaking down food down and mixing it with juices secreted by stomach lining.
2. Peristalsis in stomach helps in partial digestion of food.

c) Small intestine:

1. Peristalsis pushes the digesting food through small intestine.
2. It helps to mix the chyme to help in the digestive process.
3. Peristalsis also helps in absorbing nutrients from the digesting food into the blood.

d) Large intestine:
Peristaltic movements help to propel feces along the large intestine through colon, to the rectum for expulsion from the body.

Question 13.
How can you justify the enteric nervous system as the second brain of the gut?
(OR)
Write about the nervous system present beneath the digestive system.
Answer:

1. The enteric nervous system, the second brain consists of sheaths of neurons embedded in the walls of the long tube of our gut, or alimentary canal.
2. The second brain measures about nine meters to end from the oesophagus to the anus.
3. The second brain contains some 100 million neurons, more than in either the spinal cord or the peripheral nervous system.
4. This multitude of neurons in the enteric nervous system enables us to “feel” the inner world of our gut and its contents.
5. Enteric nervous system contains mass of neural tissue filled with important neurotransmitters.
6. This reveals that it does much more than merely handling digestion or inflict the occasional nervous pang of hunger.
7. Enteric nervous system stimulates and coordinates the breaking down of food, absorbing nutrients and expelling of waste.
   Thus equipped with its own reflexes and senses, the second brain can control several gut functions often independently of the brain.
8. Several scientists also believe that the enteric nervous system is a way too complicated to have evolved only to make sure things move through and out of our gut smoothly.
9. Hence we can justify that the enteric nervous system as the second brain of the gut.

Question 14.
Rajesh feels hungry upon seeing food. Sheela says no more food as she is not hungry. What makes Rajesh hungry and what suppresses Sheela’s hunger?
Answer:

1. When glucose levels in the blood fall, we get hunger pangs in the stomach. Feeling hungry lies in the physiology of blood circulation.
2. The secretion of the hormone GHRELIN starts in the stomach when it goes empty.
3. Hunger contractions start to occur in the stomach due to hunger generating signals that reach the brain from the stomach due to ghrelin.
4. So Rajesh effected with secretion of ghrelin in his stomach and he felt hungry when he saw food.
5. Sheela was not affected with secretion of ghrelin in her stomach. She felt that her stomach is full.
6. When we feel the stomach is full and there is no need of food any more, another hormone LEPTIN is secreted that supresses hunger.

Question 15.
How are taste and smell related?
(OR)
What is the relationship between taste and smell?
Answer:

1. Taste and smell are closely related.
2. This close relationship is most readily seen in how we perceive the flavours of food.
3. Anyone with severe cough and cold cannot make out the difference in the taste of certain food items.
4. Actually, what is really being affected is the flavour of the food , or the combination of taste and smell.
5. That is because not only the taste but also the food odours are being defected.
6. However, interactions between the senses of taste and smell enhance our perceptions of the foods we eat.
7. Smell of the food flavour gives a similar taste to food.

Question 16.
List out the sphincter muscles of the food canal you have observed and give a brief description.
(OR)
What are the different types of sphincter muscles present in the digestive canal?
Answer:
There are different sphincter “muscles in the food canal. They are :

1. Esophageal sphincter
2. Cardiac sphincter
3. Pyloric sphincter
4. Anal sphincter and
5. Ileocecal value or sphincter.

1. Esophageal sphincter:

1. This allows entry of bolus into the oesophagus,
2. It also reduces back flow from the oesophagus to pharynx.

2. Cardiac sphincter:

1. It is present where oesophagus meets the stomach,
2. It’s location is almost directly in front of the heart,
3. It allows food from oesophagus into the stomach.

3. Pyloric sphincter:

1. It is present at the opening called pylorus, located at the end of the stomach,
2. Pyloric sphincter allows only small quantities of food into duodenum at a time.

4) Anal sphincter:

1. It is located at the anus, the end of the digestive system,
2. The release of waste is controlled partly, voluntarily by anal sphincter.

5) Ileocecal value:

1. It is situated at the junction of the small intestine (ileum) and the large intestine (colon),
2. It’s function is to limit the colonic contents into the ileum.

Question 17.
What happens if salivary ducts are closed?
(OR)
What happens if saliva is not produced by salivary glands?
Answer:
If salivary ducts are closed the following consequences may occur:

1. If salivary ducts are closed saliva will not release into the mouth, the mouth becomes dry.
2. We can’t taste the food.
3. Saliva secretes an enzyme called salivary amylase which breaks down the carbohydrates in food into dextrose and maltose sugar.
4. If saliva is not secreted in the mouth carbohydrates remains unchanged digestion will not completed.
5. Due to absence of saliva food will not get moistened, chewing and swallowing becomes difficult.
6. If salivary ducts are closed, the salivary glands become swollen and it leads to pain.

Question 18.
If size and shape of small intestine is like oesophagus what will happen?
Answer:

1. If size and shape of small intestine is like oesophagus the height of the person should be more than 22 feet as the length of the small intestine is about 22 feet. So it will not fit in the human body.
2. For the complete digestion of the food to occur, it has to stay in small intestine for 3 to 4 hours.
3. Otherwise digestion will not be completed and nutrients are not absorbed into blood . in the small intestine.
4. The tube like nature of small intestine as that of oesophagus will not provide increased surface area for complete absorption of nutrients.

Question 19.
Prepare a questionnaire to understand nervous coordination in the digestion process.
(OR)
What are the questions you are going to ask your teacher about nervous coordination in the digestion process?
(OR)
Prepare a questionnaire for an interview with a doctor to understand the nervous coordination in the digestion process.
Answer:

1. What is enteric nervous system?
2. Why the enteric nervous system is known as second brain?
3. How nervous system plays an important role in digestion of food?
4. Which nervous system controls the release of saliva from salivary glands?
5. Which cranial nerve controls the movement of muscles in the jaw?
6. The mechanism for swallowing is under the control of?

Question 20.
What experiment do you perform to understand action of saliva on flour? Explain it’s procedure and apparatus that you followed.
(Activity – 7)
(OR)
i) Explain the procedure followed in the experiment conducted to understand the action of saliva on starch.
ii) What apparatus and chemicals are used to do this experiment?
(OR)
Write the experiment you have performed in your school laboratory to know the action of Saliva on flour. How did you test the pH of Saliva?
(OR)
Explain the experiment conducted by your teacher in your class to show the action of saliva on the starch.
Answer:
Aim: To understand the action of saliva on flour.
Apparatus:

1. Two test tubes
2. Water
3. Ata flour
4. Water glass and
5. Iodine solution.

Procedure:

1. A test tube is taken and half of the test tube is filled with water.
2. A pinch of flour is added.
3. To mix flour with water, test tube as shaken.
4. Few drops of flour mixture is taken in a watch glass and test for the presence of starch by putting a drop of diluted tincture Iodine in it.
5. A blue black colour confirms the presence of starch.
6. Divide the mixture into two equal halves by transferring it to another test tube.
7. Both the test tubes have the same amount of solution.
8. Add a teaspoon of saliva to one of the test tube and mark it.
9. Do not add anything in the other test tube.
10. After 45 minutes add a drop of dilute Tincture Iodine solution to test tubes containing the solutions.

Observation:

1. Saliva containing flour mixture becomes slurry. It doesn’t show any change.
2. But in the second test tube with only flour mixture turns blue colour.

Conclusion:

1. Saliva in the test tube converts flour into sugar. So no change is observe here.
2. In the second test tube containing only flour mixture turns blue black.

(OR)
i) Answer:

1. Add a spoon of starch to the water taken in a test tube to make starch solution. Starch solution is divided into two equal parts in two test tubes.
2. Add a little saliva to one of the above test tube and the other without adding saliva and keep them a side for some time.
3. Add a drop of dilute iodine to both the test tubes. The test tube added with saliva doesn’t turns to blue black because the starch is broken down into smaller units called sugar by the saliva.
4. The other part which is not added with saliva turns into blue black, as it has starch without any change.
   So this experiment proves saliva converts complex carbohydrates into simple sugars.

ii) Answer:
Test tubes, water glass, flour, iodine, saliva.

Question 21.
Suggest a simple experiment to prove the role of palate in recognizing taste.
(OR)
How do you prove that palate has a role in recognizing taste?
(OR)
“Taste is connected to the tongue and palate”. Write an activity to prove it and write your observations.
Answer:
Experiment to prove the role of palate in recognizing taste
Aim: To prove the role of palate in recognizing taste.
Apparatus: Sugar crystals, Stop watch.
Procedure:

1. Place some sugar crystals on the tongue.
2. Keep mouth opened and see that tongue does not touch the palate.
   
3. Record the time from the moment we placed the crystals on the tongue till we get the taste by using stop watch.
4. Now repeat the test by placing the sugar crystals on the tongue pressing it against the palate.
5. Record the time from placing sugar crystals to getting the taste.

Observation: From the above activity we know that taste can be identified easily when the tongue is pressed against the palate.
Result: We can easily identify the taste of the substance we can identify the taste of it in lesser time.

Question 22.
Collect information related to feeling hunger from your school library and prepare a note on it.
Answer:

1. Generally we feel hunger when our stomach goes empty.
2. When our stomach goes empty Ghrelin hormone is released and it causes the feeling of hunger.
3. As well leptin hormone also released, but it causes the feeling of suppression of hunger.
4. Not only these, when we saw a colourful and good smelling food, automatically we feel hunger. So, the sight of seeing a good food also causes feeling of hunger.
5. If the food doesn’t have good colour, texture, good smell we can’t eat, even though it is a good food.
6. All the feelings towards food are recieved by our eyes, nose, tongue.
7. From these, information is sent to brain, from there signals are sent to stomach and causes feelings either positive or negative.
8. Hormones are also responsible for most of the feelings of hunger.

Question 23.
Draw the block diagram of showing sensation of taste from food material to brain.
Answer:

Question 24.
Draw a neatly labelled diagram showing a peristaltic movement in oesophagus Explain the importance of mucus on the walls of food pipe.
(OR)
In the food pipe, the food bolus is propelled into the stomach by peristaltic movement Represent this action with a diagram.
Answer:
Importance of mucus on the walls of food pipe :

1. The walls of the food pipe secrete a slippery substance called mucus.
2. Mucus lubricates and protects the oesophgeal walls from damage.
3. This helps the food bolus to slide down easily.
4. Besides this the saliva in the bolus also helps in easy movement.

Question 25.
Draw a schematic diagram of villus in small intestinp. Explain how digestive system coordinates with circulatory system.
(OR)
Draw the diagram of villi in small intestine and lable its parts.
Answer:
Coordination of digestive system with circulatory system :

1. After the completion of digestion in small intestine, it enters into the blood through villi.
2. In blood the digested food gets oxidised after that energy is released.
3. Releasing of energy from fot^d occur only when it enter into the blood.
4. So, there is a great coordination between digestive and

Question 26.
The mere smell or sight of food stimulates hunger . Describe the process through a neat diagram.
Answer:

1. The mere smell even the mere sight of delicious food stimulates the hunger.
2. When we smell, the air borne substances get dissolved in the watery film of nasal mucus.
3. The chemoreceptors in nose are otherwise called olfactory receptors which trigger signals in the form of nerve impulses to the brain where smell is defected.
4. The amount of the neurosecretory protein hormone ghrelin in the blood increases as a result of visual stimulation images of food.
5. Hunger contractions start to occur in the stomach due to hunger generating signals that reach the brain.
6. It is believed that the diencephalon in fore brain and vagus nerve (10th cranial nerve) plays an important role in carrying these signals to brain.
7. Hunger pangs continue up to 30-45 minutes.
8. Increase ¡n ghrelin levels results in sensation of hunger and motivation to consume food.

Question 27.
With the help of a diagram show the movement of food from mouth to the stomach. What muscles and nerves are involved in the movement of food and what is this action called as ? (OR)
Draw a diagram of peristaltic movement of food in oesophagus of elementary canal. Write how it performs.
Answer:
The muscles involved in movement of food from mouth to stomach :

1. The circular muscles of the mouth enable the food to be pushed into the oral cavity and to be moved around.
2. The surface muscles of the jaw help in biting and chewing actions and move the jaw up, down, forward and backward.
3. Contraction and relaxation of circular and longitudinal muscles in the oesophagus bring in a wave like motion that propels the bolus into stomach by the action called peristalsis.
4. As the food approaches the closed ring of pyloric sphincter the surrounding muscles relax and allow the food to pass.
5. The muscles of the upper part of the stomach have to relax and accept large volumes of swallowed material.

Nerves involved in the movement of food:

1. The fifth cranial nerve has been found to control the movement of muscles in the jaw.
2. Peristalsis in oesophagus is under the control of autonomous nervous system.

Question 28.
Prepare a cartoon on Pavlov’s experiment with a suitable caption.
Answer:

Question 29.
How do you appreciate stomach as a churning machine? How does this coordination
Answer:

1. The stomach acts like a churning machine, churning the food around to break it into even smaller pieces.
2. Mechanical mixing of food in stomach occurs by peristalsis, which is waves of muscular contractions that move along the stomach wall.
3. This allows the mass of food to further mix with the digestive enzymes.
4. Due to churning of food in stomach, a mixture that resembles thick cream called chyme is formed.
5. All the muscles in the stomach works with such a great coordination.
6. Hence we can call stomach as a churning machine.

Question 30.
There is a great variety in diversified life processes, express your feelings in the form of a poem.
Answer:

POEM
Life is a process of discomfort and pain.
Learn to handle it all with courage and sane
Remember the bliss waiting for you
Nutrition, excretion, respiration all are essential in our life.
Reproduction makes our species go on and on forever.
Autotrophs and heterophs are brothers.
Depend on each other In a systematic way.
So have courage to learn more tricks.
Search for happiness.
In life that survive.

Question 31.
Suggest any two important habitual actions to your friend while eating food, keeping in view of this chapter.
Answer:

1. Masticate the food thoroughly in the mouth.
2. Do not swallow food without chewing properly or do not eat in hurry.
3. Eat small quantities of food at regular intervals for efficient digestion and absorption of nutrients.
4. Eat the food that emit good smell and has good taste to eat.
5. Do not eat too hot and too cold items.

Fill in the blanks.

1. 3:2:1:2 is the ratio of our dentition. Here 1 represents ———–.
2. Large protein molecules are broken down in ———– of digestive tract.
3. ———– is the strong acid which is secreted during digestion.
4. Olfactory receptors present in ———– triggering signals to brain.
5. pH of saliva is ———– in nature.

Answer:

1. Canine
2. Stomach
3. HCl
4. Nose
5. Alkaline nature

Fill in the blanks with suitable words given below.

Fluctuations of hormone —–(i)—– levels results in sensation of hunger and motivation of consuming food. When you feel your stomach is full and there is no need of food any more. Another hormone —–(ii)—– that gets secreted suppresses hunger. When we take food into the mouth it has to be chewed thoroughly. For this purpose the —–(iii)—– muscles help in chewing actions, while the —–(iv)—– muscles of the jaw moves the jaw up,down, forward and backward during food mastication. The —–(v)—– nerve controls the muscles of the jaw. Under the action of —–(vi)—– nervous system Saliva is released by the salivary glands moistens the food to make chewing and swallowing easier. The salivary —–(vii)—– in the saliva breaks down the starch into sugars. As a result of chewing the food is transported into the oesophagus by the action of swallowing which is coordinated by the swallowing centre in the —–(viii)—– and the —–(ix)—–. The tongue which is gustatory recognizes the taste and —–(x)—– nerve plays an important role in sensation of taste.

Choose the right ones.
i) leptin, ghrelin, gastrin, secretin.
ii) ghrelin, leptin, secretin, gastrin.
iii) deep muscles, surface muscles, circu lar muscles, striated muscles.
iv) surface muscles, deep muscles, neck muscles, long muscles.
v) fifth cranial nerve, second cranial nerve, fifth facial nerve, spinal nerve.
vi) central nervous system, peripheral nervous system, autonomous nervous system.
vii) lipase, sucrase, galactase, amylase.
viii) medulla oblongata, cerebrum, 8th spinal nerve, cranial nerve, 7th cranial nerve.
ix) Pons varoli, brain stem, medulla oblongata, mid brain.
x) 6th cranial nerve, 5th cranial nerve, 10th cranial nerve, optic nerve.

Answer:
i) ghrelin
ii) leptin
iii) surface
iv) deep
v) fifth cranial
vi) autonomous
vii) amylase
viii) medulla oblongata
ix) brain stem
x) fifth cranial nerve

Choose the correct answer.

1. In which of the following situations you can taste quickly? [ ]
   A) Put sugar cristals on tongue
   B) Put sugar solution on tongue
   C) Press the tongue slowly against the palate
   D) Swallow directly without grinding and shredding
   Answer: C
2. Peristalsis is because of [ ]
   A) Contraction of longitudinal muscles
   B) Contraction of circular muscles
   C) Under control of autonomous nervous system
   D) Digestive secretions
   Answer: C
3. Sphincter that helps in opening of stomach into duodenum [ ]
   A) Cardiac
   B) Pyloric
   C) Anal
   D) Gastric
   Answer: B
4. Glucose and amino acids are absorbed through the following part of villus [ ]
   A) epithelial cells
   B) blood capillary
   C) lymphatic vessel
   D) all
   Answer: A
5. The region in brain portion that controls hunger signals [ ]
   A) medulla
   B) diencephalon
   C) cerebrum
   D) mid brain
   Answer: B
6. Human organism is an internal combustion machine because of …. [ ]
   (OR)
   Human being is an “Internal combustion machine” because he/she
   A) assimilation of energy from food
   B) liberate CO₂ during respiration
   C) expel waste food at the end state of digestion
   D) secrete powerful digestive juices
   Answer: A

10th Class Biology 7th Lesson Coordination in Life Processes InText Questions and Answers

10th Class Biology Textbook Page No. 145

Question 1.
How do we know that we need food?
Answer:
When we feel hungry then we know that we need food.

10th Class Biology Textbook Page No. 146

Question 2.
What plays a major role to identify stale food?
Answer:
Smell or odour plays a major role to identify stale food.

Question 3.
If you are having a tasty dish do you think the smell of it increases your appetite?
(OR)
Do the smell of tasty dish increases our appetite?
Answer:
Yes, the smell of tasty dish increases our appetite.

Question 4.
What are your observations after chewing cumin, sounf, potato and apple?
Answer:
If we chew cumin, sounf, potato and apple we observe in order to taste the food material the food should dissolve in saliva.

10th Class Biology Textbook Page No. 148

Question 5.
Are there any other sensation that affect taste?
Answer:
Temperature (hotness), coldness are the sensations that affect taste.

Question 6.
What happens to your taste sensation while sipping hot milk or tea?
Answer:
We find something more tasty while we sipping hot milk or tea.

Question 7.
What do you think could be the range of temperature for us to relish food items?
Answer:
30°C to 35°C could be the range of temperature for us to relish food items.

10th Class Biology Textbook Page No. 149

Question 8.
What do you think that would happen if the salivary glands did not function in our mouth?
Answer:

1. If the salivary glands do not function in our mouth, saliva will not release and the food do not get moistened and chewing it is difficult.
2. The taste of the food cannot be identified.
3. Carbohydrates in the food cannot be broken down and changed to dextrose and maltose molecules.

Question 9.
Suppose your taste buds were affected what would happen to your interest in haying food?
Answer:
If my taste buds were affected I cannot identify the taste of food and also loose interest in having food.

10th Class Biology Textbook Page No. 151

Question 10.
Does the level of saliva secretion change due to presence of food in the mouth?
Answer:
Yes, the level of saliva increases due to the presence of food in the mouth.

Question 11.
Can the process of chewing go on in the absence of saliva?
Answer:
Yes, the process of chewing go on in the absence of saliva. But it is very difficult to chew food and swallow it.

Question 12.
Does the saliva have any other roles to play?
Answer:
The enzyme present in saliva that is salivary amylase converts large molecules of carbohydrates into small molecules of sugar like maltose and dextrose.

Question 13.
What is the use of such an increase in surface area of food?
Answer:
It helps in more surface area for the enzyme to act.

Question 14.
What about the nature of medium for salivary amylase to act on food component?
Answer:
The nature of medium for salivary amylase to act on food component is alkaline.

Question 15.
If we swallow food material directly without mastication what will happen?
Answer:
If we swallow food material directly without mastication, the food will not get digest easily and completely.

Question 16.
Do you think the pH of our mouth changes?
Answer:
Yes, the pH of our mouth changes from acidic to alkaline by the release of saliva from salivary glands.

10th Class Biology Textbook Page No. 152

Question 17.
What are the different systems that contribute to the proper functioning of digestion in the mouth?
Answer:
Endocrine, muscular, nervous systems contribute to the proper functioning of digestion in the mouth.

Question 18.
After the digestive process in the mouth where does the food move to?
Answer:
After the digestion in the mouth the food move to oesophagus.

10th Class Biology Textbook Page No. 153

Question 19.
What are the systems that come into play for swallowing food?
Answer:
Skeletal system, nervous system and digestive systems come into play for swallowing food.

Question 20.
What does the schematic diagram tell us about the oesophagus?
Answer:
The schematic diagram of the oesophagus tells about its structure, secretion and function.

Question 21.
What kind of the tube is oesophagus?
Answer:
Oesophagus is a muscular and an elastic tube.

Question 22.
How does mucus help in passage of food?
Answer:
Mucus helps in lubricating and protecting the oesophageal wall and helps the bolus to slide down easily in the oesophagus.

10th Class Biology Textbook Page No. 154

Question 23.
What makes the movement of the food bolus in the oesophagus easy?
Answer:

1. Mucus helps the food bolus to slide down easily.
2. Peristaltic movements of the walls of oesophagus also make the movement food bolus in the oesophagus easy.

Question 24.
Why do you think the stomach is structured like a bag rather than a tube like an oesophagus?
(OR)
Why stomach is structured like a bag rather than like a tube?
Answer:

1. The food taken has to remain in the stomach for a long time for proper digestion with digestive juices and enzymes.
2. Different kinds of muscles churns the food by contraction and relaxation to form chyme.
3. If it was like a tube the food would just pass down without under going much changes and cannot remain in the stomach for long time.

Question 25.
What sets such processes into action?
Answer:

1. When the food is in the oral cavity, the nerves in the cheek and tongue are stimulated.
2. These carry messages in the form of nerve impulses to the brain.
3. They messages are transmitted from the brain, to the wall of the stomach, and stimulate the gastric glands to produce gastric juice.

10th Class Biology Textbook Page No. 155

Question 26.
What stimulates stomach muscle into action?
Answer:
The nervous system stimulates stomach muscle into action.

Question 27.
What causes the stomach to churn and mix the food?
Answer:
The contractions of the stomach muscles squeeze and mix the food with the acids and juices of the stomach.

Question 28.
Why should only a small quantity of food be passed from stomach to duodenum?
Answer:
For the complete digestion of chyme, only a small quantity of it be passed from stomach to duodenum.

Question 29.
What is involved in bringing about peristalsis?
Answer:
Contraction and relaxation of the muscles present in various parts of gut bring about peristalsis.

Question 30.
What is the direction of peristalsis? Which end of the gut does it begin?
Answer:
The direction of peristalsis is forward direction that is from mouth to anus.

Question 31.
What happens if the direction of peristalsis is reversed?
Answer:
If the direction of peristalsis is reversed the food present in the gut moves backwards.

10th Class Biology Textbook Page No. 157

Question 32.
Why do you think small intestine is long and coiled?
Answer:
The small intestine is long and coiled because the food has to stay for more time for complete digestion and absorption.

Question 33.
What process is involved in this process of absorption?
Answer:
Selective absorption of nutrients by the villi of small intestine is involved in absorption.

Question 34.
What is the relation between finger-like structures and paper folds?
Answer:

1. Finger-like structures increase the surface area.
2. The space inside the paper folds is very much high. So area is increased.
3. So increase in surface area is the relation between finger-like structures and paper folds.

Question 35.
What systems do you think are working together?
Answer:
The digestive system and circulatory system are working together.

Question 36.
Do you think those systems work together in the whole length of the digestive canal? Why / Why not?
Answer:
No, these systems are not working together in the whole length of the digestive canal. The digested food material is absorbed only in the small intestine but not elsewhere in the gut.

10th Class Biology Textbook Page No. 158

Question 37.
Often you may have experienced that if you have tension for some reason you start having loose motions. What does this show us?
Answer:
If we are tensed for some reason, the enteric nervous system or second brain loses control over the gut. Hence without our intervention, loose motions occur.

10th Class Biology Textbook Page No. 159

Question 38.
What moves out of the gut?
Answer:
The indigested food material moves out of the gut.

Question 39.
Two major pathways of waste expulsion are shown above. Which of the two do you think happens exclusively through the gut?
Answer:
Indigested food matter is expelled in the form of stool from the gut.

Question 40.
What controls the exit of stools from the body?
Answer:
The two muscular layers present In the anal sphincter control the exit of stools from the body.

Question 41.
Do you think the control is voluntary? Why / Why not?
Answer:
Yes, the control is voluntary in adults and it is involuntary in infants.

Question 42.
Did we have a sphincter in any other part of the digestive canal? Where was it?
Answer:
Yes. We have a sphincter at the opening where stomach opens into duodenum (small intestine).

10th Class Biology Textbook Page No. 160

Question 43.
What is the fate of the digested substances that move into blood from the intestine?
Answer:
The digested substances reach each cell of the body through circulatory system. There it gets oxidised and release energy.

Question 44.
Where is the energy stored?
Answer:
The energy is stored in the cells as ATP.

Question 45.
Which system do you think will remove the excess salts from our body?
Answer:
The excretory system remove the excess salts from our body.

Question 46.
What would be the path of salt removed from gut to the outside of our body?
Answer:

1. The digested food containing salts will be absorbed into the blood stream in small intestine.
2. The circulatory system supplies this to kidney through renal artery.
3. In the kidney salts are filtered and sent out of the body along with urine.
4. Some of the salts also supplied to the skin. They will be sent out of the body in the form of sweat.

10th Class Biology 7th Lesson Coordination in Life Processes Activities

Activity – 1
Observe the following table, identify and tick those options that you think makes you feel hungry.
Table

Smell of food	Taste of food	Sight of food	Being tired and exhausted	Need of food	Thought of food
✓	✓	✓	✓	✓	✓

i) What stimulates hunger?
Answer:
Smell of food, sight of food and need of food stimulates hunger.

ii) What would be the result of stimulation of hunger?
Answer:
Hunger pangs occur in the stomach.

iii) Which system do you think would send the signals to make us realize that we are hungry?
Answer:
Nervous system.

iv) What kinds of controls are exercised during sensation of hunger? Are they hormonal or nervous or both?
Answer:
They are both hormonal and nervous.

v) Can you suggest any four systems involved in the process of generating hunger sensation?
Answer:
Digestive system, Endocrine system, Circulatory system and Nervous system.

Activity – 2
Observation of how our taste is affected by the sense of smell. (OK) How our taste is affected by the sense of smell?

1. First, close your nose with your fingers.
2. Pop in some zeera in your mouth and chew it for some time.
3. After that chew some sounf.
4. Could you recognise the taste?
5. How long it taken to know the taste?
6. After sometime wash your mouth and repeat the activity by chewing a piece of an apple followed by a potato (remember to close your nose)

Could you know the taste of both or did it taste the same? Why?
Answer:
No, because taste buds couldn’t send the taste signals to brain.

Observation :

1. We can taste the food that is in the form of liquid only.
2. Only after the dissolved food enters into the cup like taste buds, the sense of taste is carried to the brain for analysis. Then only we will know the taste of food material.
3. Similarly olfactory receptors which trigger signals in the form of nerve impulses to the brain where smell is detected.

i) What happens when we put a food material in our mouth?
Answer:
Our mouth salivates.

ii) Name the parts in the mouth that help us to taste food.
Answer:
Papillae (taste buds), palate.

Activity – 3

1. Take a pinch of asafoetida powder/garlic and rub it on hand kerchief/tissue paper.
2. Close your eyes and smell it.
3. Then try to identify taste of different types of food materials with the help of your friend.

i) Does garlic have a stronger scent than apple? How do you think the stronger scent affect your sensation of taste?
Answer:
Yes, garlic have a stronger scent than apple. The stronger scent motivate us to eat different types of foods.

ii) How many food materials you have identified correctly?
Answer:
Seven.

iii) Write a few lines on the relation between smell and taste.
Answer:

1. Taste and smell are intimately entwined. This close relationship is most apparent in how we perceive the flavour of food.
2. Taste itself is focussed on distinguishing chemicals that have sweet, salty, sour, bitter or umami taste.
3. However interactions between the senses of taste and smell enhance our perceptions of the foods, we eat.

iv) Have you ever felt that a particular food is tasty just by looking at it?
Answer:
I felt so many times. In general, we prefer the food material, which is attractive to our eyes and flavour to nose, then we taste it.

Activity – 4
What is the role of different parts of the mouth in helping us to taste keeping sugar crystals over the tongue?

1. Place some sugar crystals on the tongue and keep mouth opened and see that your tongue dosen’t touch the palate.
2. Record the time from the moment you placed the crystals on your tongue till you got the taste by using stop watch.
3. Now repeat the test by placing the sugar crystals on the tongue and pressing it against the palate.
4. Record the time from placing sugar crystals to getting the taste. Or put a drop of sugar solution on your tongue using a dropper.

Observation :
Based on the above activity we know that taste can be identified easily when the tongue is pressed against the palate.
i) Can we taste on dry tongue?
Answer:
No. We can’t taste on dry tongue.

ii) Which way helped you taste faster? Why?
Answer:
Taste can be identified faster when the tongue is pressed against the palate.
When the tongue is pressed against the palate the food substance is pressed against the opening of the taste bud letting it reach taste celjs triggering taste signals. Finally the taste is recognised in the brain.

Activity – 5
How do you show that the breakdown of food by using the model of chalk piece kept in vinegar?

1. Break a piece of chalk into two halves.
2. Crush one half to tiny pieces leaving the other as it is.
3. Take two small mineral wafer bottles QA ltr bottle) cut them into two equal halves and discard the upper portion.
4. Now we have two beakers from the lower cut portion.
5. Fill them half with vinegar and add the crushed chalk to one beaker and the other uncrushed half chalk to the other.
6. Observe them after half-an-hour or so.

i) Which one dissolved faster the crushed chalk or the whole one?
Answer:
Beaker with crushed chalk dissolved faster than the whole one.
This experiment tells us the need of mechanical crushing of food the mouth to increase surface area for action of substances that aid in digestion.

ii) How does this process of mechanical crushing go on in the mouth?
Answer:
Mechanical crushing of food goes in the mouth by chewing.

iii) Which parts in the mouth are involved in this?
Answer:
Teeth and tongue.

iv) What are the systems involved in this process?
Answer:
Digestive system, Nervous system, Muscular system.

Activity – 6
Observe the diagram and answer the questions and fill the table.
i) Observe the model or chart of jaw, on the basis of the figure try to guess what are the functions molars could be?
Answer:
Chewing and grinding.

ii) What do you think could be the function of inscisors?
Answer:
The function of inscisors is biting the food.

iii) Which set of teeth helps in grinding food?
Answer:
Premolars and molars.

iv) Which set helps in tearing food?
Answer:
Canines help in tearing food.

v) What is your dental formula?
Answer:
is the dental formula.

Table

Name of teeth	Number	Shape	Function
Incisors	8	Chisel, sharp edges	Biting
Canines	4	Sharp, pointed edges	Tearing
Premolars	8	Diamond shape blunt and flat	Chewing and grinding
Molars	12	Rectangular, blunt and flat	Chewing and grinding

Activity – 7
Testing pH of mouth at intervals of one hour.

1. Collect a strip of pH paper with a colour chart from a chemistry teacher.
2. Take a small piece of the pH paper and touch it to your tongue.
3. Match the colour with the colour chart and note the pH.
4. Take some readings after having your food at lunch break.
5. Compare your readings with that of your friend.
6. Take at least 4 readings.

Table

S.No.	Name of the Student	pH value before lunch	pH value after lunch	pH value after an hour	pH value after 2 hrs
1.	Sagar	7.4	6.8	7.0	7.4
2.	San jay	7.4	6.8	7.0	7.4
3.	Raju	7.1	6.9	7.0	7.1
4.	Krishna	7.3	6.8	7.0	7.3
5.	Kiran	7.4	6.8	7.0	7.4
6.	Yadav	7.2	6.7	7.0	7.2

i) What is the usual range of pH of your mouth Acidic (or) Basic
Answer:
The usual range of pH of our mouth is more or less 6.5. At low level the saliva is acidic and at high level it is basic.

ii) Did you observe any change in pH after eating? What may have caused the change?
Answer:
Yes, 1 observed the change in pH. Bicarbonates in saliva changed that into basic.

iii) In what kind of pH do you think salivary amylase acts well?
Answer:
In the pH range 7.2 to 7.4 it acts well in alkaline medium.

iv) Does this type of food have any role to play on the pH of our mouth?
Answer:
If the food that enters is acidic it will be converted into basic stuff and then it is swallowed.
Based on the above tests we know that salival secreted causes the medium to change to alkaline as it aids in action salivary amylase.

Activity – 8
Making a model of oesophagus to observe how bolus moves forward.

1. Take a piece of waste cycle tube and insert one or two potatoes into it.
2. Lubricate the inner side of the tube with oil.
3. In the same way smear oil over potatoes.
4. Insert oil coated potatoes in the tube.
5. Now try to push the potatoes by squeezing the tube.

i) How do you squeeze the tube to make the potatoes pass through?
Answer:
By pushing the potato from behind.

ii) Do you think that the muscles in the wall of the oesophagus have to do something like this?
Answer:
Yes.

iii) How did oil help you in pushing the potatoes through the pipe?
Answer:
Oil acted as a lubricant to push the potato easily in the forward direction.

Activity – 9
How is the stomach protected from the secretions of its own acids?

1. Take two similar green leaves.
2. Grease one leaf with petroleum jelly, leave the other free.
3. Add 1 or 2 drops of some weak acids on both the leaves.
4. Observe them after half-an-hour or so and write your observations.

i) Which leaf was effected by the acid?
Answer:
The leaf to which petroleum jelly was not applied.

ii) What kind of change did you observe in the leaves?
Answer:
The colour of the leaf changes.

iii) What saved the other leaf from the effect of acid?
Answer:
Petroleum jelly.
From the above activity we can conclude that mucus secreted by the walls of stomach protects stomach from the harmful effects of hydrochloric acid.

Activity – 10
Paper tube and folded papers.

1. Provide students with a piece of paper.
2. Let them calculate the area of one side of the paper and make a roll of it.
3. Try to fill the tube by inserting few folded papers as much as possible in it.
4. Pull out the papers from the tube, unfold them and find out the whole area of the papers.

i) Compare the area of the folded papers with that of the roll. Do you find any increase in the area ? If so try to find out the reasons?
Answer:
Area is increased. The space inside the folded papers is very much high. So we can insert as many folded papers as we could.
From the above activity we can infer that the inner surface of the small intestine contains thousands of finger-like projections called villi which increase the surface area of absorption of nutrients in small intestine.

These AP 10th Class Social Studies Important Questions 3rd Lesson Production and Employment will help students prepare well for the exams.

AP State Syllabus 10th Class Social 3rd Lesson Important Questions and Answers Production and Employment

10th Class Social 3rd Lesson Production and Employment 1 Mark Important Questions and Answers

Question 1.
What is under employment?
Answer:
Under employment is the situation, where people are apparently working but all of them are made to work less than their potential.

Question 2.
In which sector is the disguised unemployment found predominantly in India today? Why?
Answer:
In agricultural sector we find disguised unemployment, because more than the required persons are engaged in the work of agriculture.

Question 3.
Suggest the reforms for the betterment of unorganized sector workers.
Answer:
Reforms for the betterment of unorganized sector workers:

1. Increase in wages.
2. Security in jobs.
3. Overtime work should be paid.
4. Facilities and safety at work places.
5. Medical facilities.
6. Sick leave provision.

Question 4.
Write examples for intermediate goods.
Answer:

1. Paddy
2. Rice
3. Yarn
4. Rubber

Question 5.
Give an example for underemployment.
Answer:

1. Though there is no sufficient work, many agricultural labourers work less than their potential.
2. In the service sector – painters, plumbers, repair persons, etc.

Question 6.
What does the unorganized sector consist of?
Answer:
The sector in which small and scattered units are outside the control of the government is called unorganized sector. It consists of low wages, no job security, no paid leaves, no health facilities, etc.

Question 7.
Observe the pie chart and answer the following questions.
Sectoral shares of employment, 2011 – 12
(a) Which sector provides less employment?
Answer:
Industry (24%)

(b) Mention any two reasons for more employment in the agriculture sector.
Answer:

1. Not enough jobs were created in the industry and service sector.
2. Irrespective of the literacy rate rural people depend on agriculture.
3. Easy employment opportunities.

Observe the information given in the table and answer questions 8 and 9.
Table: Share of Employment and Gross Domestic Product in Three Sectors

Sector	Employment (%) 2011-12	Gross Domestic Product (%) 2011-12
Agriculture	49	16
Industry	24	26
Services	27	58

Question 8.
What was the share of the agricultural sector in Gross Domestic Product?
Answer:
The share of the agricultural sector in Gross Domestic Product is 16%.

Question 9.
What was the reason for low employment in service sector though it has a major contribution to Gross Domestic Product?
Answer:
The reason for low employment In service sector though it has a major contribution to Gross Domestic Products is

• Lack of skill
• Lack of access to employment opportunities

Question 10.
Give any two examples for final goods.
Answer:
Idli, Dosa, Gar, Computer, Notebook, etc.

Question 11.
Why do people prefer to work in an organized sector ?
Answer:
Security of employment Regular salary Paid Holiday, safe working environment Gets provident fund, etc.

Question 12.
Define service sector.
Answer:
Services like transportation, communication, financing, insurance, banking, etc. are auxi¬liaries to trade or aid to trade. These services constitute service sector of trade.

Question 13.
What is primary sector?
Answer:
Primary sector is the sector which involves agricultural activities, and related activities like mining, poultry, etc.

Question 14.
What is secondary sector?
Answer:
It is the sector which is engaged in the manufacturing of goods from the raw material provided by the primary sector.

Question 15.
Define unemployment.
Answer:
Unemployment is a situation where the able-bodied persons are willing to work but are not able to get work. They are not engaged in any productive activity.

Question 16.
What is employment?
Answer:
Employment is a situation where the able-bodied persons are willing to work and are engaged in some productive activity to earn an income.

Question 17.
What is the other name of underemployment?
Answer:
The other name of underemployment is disguised unemployment.

Question 18.
What is GDP?
Answer:
The value of goods and services produced in an economy in a financial year is known as GDP.

Question 19.
Which sector is called organised sector?
Answer:
The sector which covers those enterprises where the terms of employment are regular and they have assured work is called organised sector.

Question 20.
Which sector is called unorganized sector?
Answer:
The sector in which small and scattered units are outside the control of the government is called unorganized sector.

Question 21.
Which sector is also called the service sector?
Answer:
Tertiary sector is also called service sector.

Question 22.
Which is called disguised unemployment?
Answer:
Unemployment which exists when marginal physical productivity of labour is zero or sometimes it becomes negative is called disguised unemployment.

Question 23.
Why does small scale industry need government’s support?
Answer:
Small scale industry needs government’s support for procuring raw-material and mar¬keting of output.

Question 24.
In what ways can employment be increased in urban areas? Write any two suggestions.
Answer:
Suggestions:

1. Heavy investments should be created in basic industries.
2. Means of transportation and communi¬cation should be developed.

Question 25.
Which sector is continued to prove the largest employer between 1973 to 2000?
Answer:
The agricultural sector is continued to prove the largest employer between 1973-2000.

Question 26.
Write any two activities which are the primary responsibility of the government.
Answer:
Health and Education.

Question 27.
What is meant by “final goods and services”?
Answer:
Final goods and services refer to the goods and services which are meant either for consumption by consumers or for investment by firms or organizations.

Question 28.
What are intermediate goods?
Answer:
Intermediate goods are those goods that are used in producing final goods and services.

Question 29.
Which sector is growing fast in India?
Answer:
Service sector is growing fast in India.

Question 30.
By whom is the task of measuring GDP done?
Answer:
The task of measuring GDP is done by the Ministry of Central government.

Question 31.
What does the GDP record?
Answer:
The GDP records the market value of final goods and services produced.

Question 32.
Name some acts of organized sector.
Answer:

1. Factories Act
2. Minimum Wages Act
3. Shops and Establishments Act, etc.

Question 33.
Who are in the organized sector?
Answer:
People who work in the government or with companies or large establishments are all in the organized sector.

Question 34.
Name some organizations in the service sector.
Answer:

1. Indian Railways
2. Postal & Telegraphs
3. Indian Airlines
4. All India Radio
5. BSNL, MTNL.

Question 35.
How do we count the various goods and services of each economic sector?
Answer:
We count the value of final goods and services produced in each sector during a particular year. This provides the total production of the sector for that year.

Question 36.
Why should we worry about underemployment?
Answer:
We should worry about underemployment as it decreases the standard of living of the people.

Question 37.
What do you mean by underemployment?
Answer:
Everyone is engaged in working, but no one is working to his full capacity, such employ¬ment Is underemployment.

Question 38.
Into how many sectors economic activities are divided?
Answer:
The economic activities are divided into 3 sectors primary, secondary and services.

Question 39.
What do you mean by Gross Domestic Product?
Answer:
The money value of all the finished goods and services produced within a country borders during the year.

Question 40.
What is the main source of income to your family? Among the three sectors, under which can it be categorized?
Answer:

1. My father is a farmer.
2. Hence we can say he works in the primary sector.

10th Class Social 3rd Lesson Production and Employment 2 Marks Important Questions and Answers

Question 1.
How is the Organised sector different from an Unorganised sector?
Answer:
1) The organised sector is the enterprises or places of work where the terms of employment are regular and therefore, people have assured work.
2) The unorganised sector s characterised by small and scattered units which have remained largely outside the control of the Government. In this way the organised sector is different from the unorganised sector.

Question 2.
Observe the following table and answer the questions given below,
Contribution of organised and unorganised sectors

Sector	Contribution (% of total)
	Employment	Gross Domestic Product
Organised	8	50
Unorganised	92	50
Total	100	100

a) What percentage of labour in the unorganized sector get employment?
Answer:
92%
b) Which sector get decent job security?
Answer:
Organized sector

Question 3.
What are the facilities provided to workers in the organised sector?
Answer:

1. Job security
2. Limited working hours.
3. Paid holidays.
4. Safe working environment.

Question 4.
Which measures do you suggest to improve the employment opportunities in rural area?
Answer:

1. Agriculture should be supported by the government.
2. Household industries should be encouraged.
3. Rural employment schemes should be implemented effectively.

Question 5.
Study the following pie-charts and answer the questions given below:
Shares of three sectors in GDP

a) Which sector got tremendous increase?
Answer:
Service sector.
b) Why did the share of agricultural sector decrease in G.D.P?
Answer:
Production in agriculture has not developed as per the expectations.

Question 6.
Draw the bar graph on the basis of information given in the table below.

Sectors	Employment (%)
	1972 – 73	2009 -10
Agriculture	74	53
Industrial	11	22
Service	15	25

Answer:

It shows how people depend upon these sectors for employment.

Question 7.
Observe the table and answer the questions.

Year	Agriculture	Industry	Services
1972-73	74%	11%	15%
2008-09	53%	22%	25%

The table shows the percentage of workers employed in different sectors in India in 1972-73 and 2009-10.

a) What are the major changes you observe from the above table?
Answer:

1. The agriculture sector is decreased.
2. Industry and services are increased.
3. Industry is increased two times.
4. There is a great shift from the agricultural sector to the industrial and service sectors.

b) What would be the reasons for the changes?
Answer:
Employment opportunities in the agricultural sector are reduced from 74% to 53%. In industrial sector employment opportunities are increased from 11% to 22%. Like that service sector employment opportunities are also increased from 15% to 25%.
Reasons:

1. Decline in agriculture (Problems of seeds, rainfall, MSP, power cut, water.)
2. Privatization is increased.
3. IT increased.
4. Opportunities in the second and third sector.

Question 8.
Observe below ‘Pie’ chart and analyse it.

Employment in three sectors in 2011-12
Answer:

1. There is a great shift from the agricultural sector to the industrial and service sector, (or)
2. The major changes like the percentage of workers employed decrease in agriculture and increased both in industry and ser¬vice sector are observed from the above pie chart compare with before years.
   Reasons :
3. The important reasons like change in farming methods setting up of new industries, and factories, mass production of goods by factories of lower rates than agricultural goods, high payment for workers in other sectors compared to agriculture led to employment shift from agriculture sector to service and manufacturing sectors.

Question 9.
Observe the given graph and analyse it.
Shares of different sectors in Gross Domestic Product

A – Agriculture
B – Industry
C – Trade, hotels, transport and communications.
D – Finance, insurance, real estate.
E – Community, social and personal services.
Answer:
The graph explains about the share of different sectors in Gross Domestic Product in the year of 1972 – 73.
The share of Agriculture is 43%.
The share of Industry is 22%.
The share of service sector joined together is 35%.
When compared to 1972 – 73 the share of different sectors in 2011 -12 changed,
In 2011 -12 the agriculture share is only 16%. Industrial sector share is 26%. The share of service sector joined together is – 58%. Totally in 2011 & 12 the share of agriculture is reduced. The Industrial sector share is increasing. Finally service sector share increases very high.
Suggestions: To increase the share in the agriculture sector the government should take the following measures.

1. Provide seeds, fertilizers, pesticides motors to the farmers with the subsidy.
2. The government should see that the people who are engaged in Industrial and Service sectors more than required are shifted to the agricultural sector so that the share of the agricultural sector in GDP increases.
3. The government should implement welfare schemes so that the agricultural sector flourishes.

Question 10.
Name the facilities enjoyed by the workers in the organised sector.
Answer:
Organised sector covers those enterprises or places of work where the terms of employment are regular and therefore, people have assured work. They are registered by the government and have to follow its rules and regulations which are given in various laws such as the Factories Act, Minimum Wages ] Act, Shops and Establishments Act etc. It is called organised because it has some formal processes and procedures. Workers in the organised sector enjoy the security of employment, They are expected to work only for a fixed number of hours. If they work more, they have to be paid overtime by the employer. They also get several other benefits from the employers, They get paid leave, payment during holidays, provident fund, etc. They are supposed to get medical benefits and, j under the laws, the employer has to ensure facilities like drinking water and safe working environment. When they retire, many of j these workers get pensions as well. People j who work in the government or with companies or large establishments are all in the organised sector.

Question 11.
Based on the pie charts given below write how the share of agriculture sector in the GDP has changed between 1972-73 and 2009-10?

Answer:
The share of agriculture sector in GDP has reduced from 43% to 26% from the period 1972 – 73 to 2009 -10.
The main reason is the secondary and service sector’s both gradually increase in their employment and production activities.

Question 12.
Observe the pie diagrams and answer the following.

Analyse the above two diagrams.
Answer:

1. The pie diagrams depict the sectorial share of employment.
2. The people who depend on agriculture has reduced from 74% in 1972-73 to 53% in 2009-10,
3. The employment in service sector has increased from 15% to 25%.
4. The employment in the industrial sector is doubled, i.e., increased from 11% to 22%.

Question 13.
Study the following table and prepare a paragraph describing it.

Sector	Contribution (% of total)
	Employment	Gross Domestic Product
Organised	8	50
Unorganised	92	50
Total	100	100

Answer:

1. This table tells about the employment in organized and unorganized sector and its contribution in GDP.
2. Employment in organized sector is only 8% whereas it is 92% in unorganized sector.
3. The share in GDP is the same.
4. It focuses on the conditions of the work-force depend on the unorganized sector in which the wages are low, security and respect is not observed.
5. In organized sector the employees get regular salaries, they have specific work-ing hours and they avail leaves, medical benefits and other facilities.
6. These are not available in the unorganized sector.

Question 14.
Discus different sectors of Economy.
Answer:
People are engaged in different activities to earn their livelihoods. These activities are broadly categorized into three:

1. Agriculture and related activities such as fishing, forestry, mining where nature has a dominant role in the production process.
2. Manufacture processes and other industries where goods are produced by people using tools or machines.
3. Those activities that don’t directly produce a good but provide services that are required in production and other services for people.
4. These three different sectors of the economy contribute to the national income.

Question 15.
How many types are there in services? Explain.
Answer:
Services are seen to comprise of three types.
They are a) Community, social and personal services b) Finance, insurance and real estate services and Trades, hotels, transport and communication services.

1. Community, social and personal services include public administration, defence, education, health, veterinary activities, media, library, museums and other cultural activities, etc.
2. Finance, insurance and real estate servi-ces include services of banks, post office savings accounts, non-bank financial companies, Life Insurance and General Insurance Corporation, services of brokers and real estate companies, etc.
3. Trades, hotels, transport and communication services include business, exports and imports, hotels, resorts, rail, road, water ways and airways and radio, tele¬vision, newspapers, magazines and satel¬lite services, etc.

Question 16.
Table : Read the following pie charts and answer the question.

What changes do you observe in these two pie diagrams?
Answer:

1. The above pie diagrams show the share of different sectors in GDP.
2. The share of agriculture sector has fallen from 43% to 17%.
3. The share of industrial sector has increa-sed from 22% to 26%.
4. The share of service sector has increased from 35% to 57%.
   i.e., trade and hotels from 15% to 27%, finance, insurance and real estate from 8% to 17% and community, social and personal services from 12% to 13%.

Question 17.
What is the relation between population and employment?
Answer:
The Gross Domestic Product of a country has a close relation with the total number of work¬ing people in that country. In every country, as population increases, it is essential that the country provides opportunities for those who are looking for work.

Question 18.
“The workers in the agricultural sector are underdeveloped” – support this statement.
Answer:
There are more people in agriculture than is necessary. So, even if a few people move out, 1 production will not be affected. In other words, workers in the agricultural sector are underdeveloped.

Question 19.
Explain GDP. Why are only ‘final goods and services’ counted in GDP?
Answer:

1. GDP is the sum of the money value of final goods and services produced in each sector during a particular year within a country.
2. Only the value of final goods and services are counted in GDP because the value of final goods already includes the value of all the intermediate goods.
3. To avoid double-counting we take up only intermediate goods.
4. Animal husbandry and dairy are to be encouraged. :

Question 20.
Where are most of the people employed? Why did not a similar shift out of primary sector happen in case of employment?
Answer:

1. Most of the working people are still employed in primary sector.
2. There had not been a similar shift out of agricultural sector in case of employment. The reason is:
   Secondary and tertiary sectors did not create enough jobs.

Question 21.
Suggest any two measures to create more employment in rural India.
Answer:
Some measures to create more employment in rural India :

1. Irrigation facilities should be improved.
2. Roads should be constructed.
3. More education and health facilities should be provided.
4. Agro-based industries should be encouraged.

Question 22.
Describe any three problems faced by workers in the unorganised sector.
Answer:

1. This sector follows no government rules and regulations.
2. There is no regular employment.
3. They have no job security.

Question 23.
How are the activities in the economy classified on the basis of employment conditions?
Answer:
Economic activities are classified into two sectors on the basis of employment conditions:

1. Organised sector
2. Unorganised sector.

In the organised sector, the rules and regulations of employment are given to employees and everyone has to follow these rules.
In the unorganised sector, there are no rules and regulations.

Question 24.
Write any two differences between intermediate goods and final goods.
Answer:

Intermediate goods	Final goods
1. These goods are meant for further production.	1. These are used for final consumption.
2. These are not included in GDP.	2. These are included in GDP.

Question 25.
How is the unorganised sector in the rural areas?
Answer:
In the rural areas, the unorganised sector: mostly comprises of landless agricultural labourers, small and marginal farmers, share croppers and artisans.

Question 26.
How is the unorganised sector in the urban areas?
Answer:
In the urban areas, unorganised sector comprises mainly of workers in the small-scale industry, casual workers in construction, trade I and transport, etc. and those who work as steel vendors, head load workers, garment makers, rag pickers, etc.

Question 27.
Service sector in India employs two different kinds of people. Who are they?
Answer:
Service sector in India employs the following two different kinds of people. They are:

1. The people involved in such services that man directly help in the production of goods, e.g.: people involved in transportation, communication, etc.
2. The people involved in such services that may not directly help in the production of goods, e.g: teachers, lawyers, etc.

Question 28.
“Tertiary sector is not playing any significant role in the development of Indian economy.” Do you agree? Support your answer.
Answer:
No, I do not agree with the statement.
Over the last 5 decades, the most production has increased in the tertiary sector. It replaced the primary sector. The basic services are also provided by the government and; private sector. As the income levels of the people raised, people are able to enjoy many more services like shopping, tourism, etc.
Therefore it is disputable that the tertiary sector is playing a significant role in the development of Indian economy.

Question 29.
Classify the Service Sector.
Answer:

1. Services sector comprises of community, social and personal services like public administration, defence, education, etc.
2. They also comprise finance, insurance and real estate services like banks, post-offices, LIC, etc.
3. It also comprises of services like trades, hotels, transports and communication.

Question 30.
How is gross domestic product is calculated? Give example.
Answer:

1. The total value of goods and services produced in a country is the Gross Domestic Product.
2. The value of intermediate goods is not considered for GDP.
3. Economists take the value of goods and services rather than adding the number of goods.
4. People engaged in various economic activities in the three sectors viz, primary, secondary and services produce large number of goods and services whose total is GDP.

Question 31.
What are the aims and objectives of land-less rural labourers or workers?
Answer:

1. More days of work.
2. Better wages.
3. Provision of Educational and health facilities by the government.
4. Infrastructural facilities like transportation communication, etc.

10th Class Social 3rd Lesson Production and Employment 4 Marks Important Questions and Answers

Question 1.
State why the organized sector is better than the unorganized sector.
(OR)
The organised sector offers jobs that are the most sought-after. But the employment opportunities in the organised sector have been expanding very slowly. As a result, a large number of workers are forced to enter the unorganised sector jobs, which pay a very low salary.
Do you think organised sector is better than unorganised sector? Give your opinion.
Answer:
Organised sector is better sector. The reasons are:

1. Organised sector covers those enterprises or places of work where the terms of employment are regular and therefore, people have assured work.
2. They are registered by the government 3 and have to follow its rules and regulations which are given in various laws such as the Factories Act, Minimum Wages Act, Shops and Establishments Act, etc.
3. It is called organised because it has some formal processes and procedures.
4. Workers in the organised sector enjoy j security of employment. They are expected to work only for a fixed number of j hours. If they work more, they have to be j paid overtime by the employer.
5. They also get several other benefits from the employers. They get paid leave, payment during holidays, provident fund, etc.
6. They are supposed to get medical benefits and, under the laws, the employer has j to ensure facilities like drinking water and a safe working environment.
7. When they retire, many of these workers get pensions as well.
8. People who work in the government or with companies or large establishments are all in the organised sector

Question 2.
What is GDP ? How do we estimate GDP?
Answer:
G.D.P. (Gross Domestic Product):

1. For the country as a whole, we use the total value of goods and services produced in a country as the indicator of income for the country.
2. The technical term to denote this value is Gross Domestic Product (GDP).

Estimation of G.D.P.:

1. G.D.P. records the market value of all final goods and services produced.
2. G.D.P. records all of public and private consumption, government outlays, investments and exports less imports that occur within a defined territory.
3. Many items/services that are not sold /purchased in the market are not recorded in the G.D.P.
   Ex : Household works done by women.

Question 3.
“In the past 50 years, there has been a further shift from industry to service sector for developed countries. The service sector has become the most important in terms I of total production. Most of the working people have also shifted and are now employed in the service sector and most of the production activities are those of services and not manufactured goods. This is the general pattern observed for developed countries.”

Is there a similar pattern observed for India or is it different? Write your opinion.
Answer:

1. The pattern in India is somehow similar to that of developed countries.
2. But, there are some main differences also.
3. In India also, service sector is becoming more important nowadays.
4. But, even today the largest employer in India is the agricultural sector only.

Question 4.
“While service sector has grown, all service sector activities are not growing equally well. The service sector in India employs many different kinds of people. At one end there are a limited number of services that employ highly skilled and educated workers. At the other end, there are a very large number of workers engaged in services such as small shopkeepers, repair persons, transport persons, etc. These people barely manage to earn a living and yet they perform these services because no alternative opportunities for work are available to them.”

“The life conditions of all the people in ser¬vice sector are not the same.” – Comment.
Answer:

1. Regarding service sector, limited number of skilled workers in organised sector are getting higher wages.
2. On the other hand, the large number of unskilled workers in unorganised sector are not able to get minimum wages. They are living in miserable conditions.
3. Self employed, shop keepers, migrant labourers etc., do not have better working conditions, regular employment and other allowances.
4. They are being forced to continue in the same job due to the lack of required skills and alternative employment sources.
5. By considering these situations, the government has to plan suitable programmes for the balanced development of service sector.

Question 5.
Based on the information given below, write your observations:

Sector	Place of Residence		Sex		All workers
	Rural	Urban	Male	Female
Agriculture Sector	68	8	47	69	53
Industry Sector	17	34	34	16	22
Service Sector	15	58	19	15	25
Total	100	100	100	100	100

Answer:

1. Most of the rural workers are employed in agriculture.
2. Most of the urban workers are employed in service sector.
3. Most of the agricultural labourers are women.
4. Female workers are very less in service sector.
5. Agriculture sector offers the largest employment on the whole.
6. Industrial sector offers the least employment.

(OR)
Plot the information given below on a rough bar-graph and analyse it:
Employment in different sectors

Sector	Employment
Agriculture	53%
Industry	22%
Service	25%

Answer:

1. Agricultural sector is the largest employer In 2009-10.
2. Service sector is the second largest employer.
3. Industrial sector offers the least employment.

Question 6.
Observe the graph given below and answer the following questions:

1.  What does this graph explain about?
2. Which sector is the largest employer in India?
3. In which sector do most of the people want to be employed today?
4. Which sector offers the least employment?

Answer:

1. The graph explains about the shares of different sectors of employment in the years of 1972-73 and 2009-2010
2. The agriculture sector is the largest employer in India.
3. Service sector
4. Industrial sector.

Question 7.
Nowadays in which economic sector the job opportunities are increasing? Give reasons.
Answer:
(i) Nowadays employment opportunities are available more in secondary and tertiary sectors.
(ii) Last 50 years onwards the changes are occurred in GDP in all sectors, but employment is not increased. Yet, employment opportunities are increased in secondary and tertiary sectors.
Reasons:

1. Establishment of industries in public and private sectors.
2. Increasing of technological methods.
3. Increasing of educational facilities.
4. Due to globalisation, Multi-national companies are entered and industrial and service sectors are developed.
5. Transportation facilities are developing.
6. Migrations are increased.
7. Increasing of local foreign investment.

Question 8.
Suggest to improve labour conditions in unorganized sector.
Answer:

1. Wages to be increased
2. Regular payment of wages
3. Overtime work should be paid
4. Sick leave provision and paid leave.
5. Better working conditions
6. Retirement benefits to be provided
7. Security in jobs
8. Medical and health facilities

Question 9.
What are the differences between organised and unorganised sectors in Employment.
(OR)
How is unorganised sector different from organised sector? Explain.
Answer:

Organised Sector Center	Unorganised Sector Center
1. It has some formal processes and procedures.	1. It has small and scattered units largely outside the control of government.
2. It gives security of employment.	2. Rules and regulations are not enforced here.
3. It has fixed number of work hours, overtime will be paid by the employer.	3. Jobs here are low-paid and non-regular.
4. It provides paid leave, payment during holidays, provident fund, medical benefits, etc.	4. There is no provision of overtime, paid leave, holidays leave due to sickness, etc.
5. It also ensures pensions.	5. When there is less work, some people are asked to leave.
6. It has workers of government, companies and large establishment.	6. A lot also depends on the whims of the employer or changes in the market situation.

Question 10.
What measures should be taken to create employment in your area?
Answer:
I should implement some steps to create employment in my area.

1. At first, in which the various non-farming activities are performed in a location which falls with in a designated rural area.
2. Promoting dairy industry.
3. Should give more important to local handicrafts.
4. The second way hints at labour intensive use.
5. For self employment:
   Should provide bank loans with low rate of interests.
6. By creating cost effective school. Cyber cafes, retail outlets, transport systems etc.
7. Linking with industrial enterprises to rural citizens, better policies such as limit on work capacity and payment of minimum wages, etc.

Question 11.
Read the following paragraph and write your comments on it.
In the past 50 years, there has been a further shift from industry to service sector for developed countries. The service sector has become the most important sector in terms of total production. Most of the working people have also made a shift and are now employed in the service sector and most of the production activities are those of services and not manufactured goods.
Answer:

1. According to this paragraph many workers are shifting from industries to service sectors in developed countries.
2. The service sector plays an important and key role in economy.
3. Most of the production activities are now in service sector.
4. There are three sectors in the economy. They are agriculture, industrial and service sectors.
5. In developing countries many people depend upon agriculture sector whereas In developed countries it is the industrial sector which gives more work but recently we observe the trend that many people are shifting from industrial sector to service sector for their livelihoods.
6. I think that the people want to work in the sector which is providing more opportunities and where security, safety and respect are available.
7. Job in service sector provides these to some extent better than the other sectors the people shift toward service sector.

Question 12.
Observe the given table and analyse the share of GDP.

Sectors	2012	2013	2014	2015	2016	2017
Agriculture	16.85%	17.15%	16.79%	16.17%	16.28%	15.45%
Industry	29.4%	28.4%	27.66%	27.22%	26.58%	26.16%
Services	46.3%	46.7%	47.82%	47.91%	47.88%	48.93%

Answer:
The given table is about share of GDP. The GDP is taken from 2012 to 2017. The sectors of economy are analysed In data form. The share of GDP from agriculture is very less and it has been reducing year by year. Industries are slightly decreasing from 2013. it is 29% only in 2012. But service sector is gradually increasing.
Many people nowadays are interested in working with service sector as they feel that it is white collar job. Nobody Is interested in agriculture. No farmer is interested to make his son a farmer because in agriculture more distress is seen. Irregular rainfall, low prices (MSP), shortage of seeds, pesticides problem, fertiliser problem and so many problems, the agriculture sector is facing. In Industries also work conditions are not supportive. Agriculture is technologically up¬graded. Agriculture labourers are shifting to service, industrial sectors. Though 92% of workers are there In unorganised sector, they are contributing about 50% in GDP, Government should support the farmers and agriculture should be made a benefitable one.

Question 13.
Read the passage and comment on it.
While service sector has grown, all service sector activities are not growing equally well, Service sector In India employs many different kinds of people. At one end there are a limited number of services that employ highly skilled and educated workers. At the other end, there are a very large number of workers engaged in services such as small shopkeepers,repair persons, transport persons, etc. These people barely manage to earn a living and yet they perform these services because no alternative opportunities for work are available to them. Hence, only a part of this sector Is growing in Importance.
Answer:

1. The contribution of service sector to GDP has grown considerably.
2. But all service activities are not grown equally.
3. Only highly skilled and educated workers, which are limited in number, are earning good income.
4. Whereas a very large number of workers engaged in services such as small shopkeepers, repair persons, transport persons, etc. are a part of service sector.
5. But they barely manage to earn a good income.
6. They have no other alternative opportunity for work.
7. Hence, we can conclude that only a part of the service sector is growing.

Question 14.
Read the following paragraph and interpret it.
GDP records the market value of all final goods and services produced. But there are many items that are not sold/ purchased in the market. One important example is the work that is done at home like cooking, cleaning, organizing, bringing up children, tending to plants and cattle, etc. In most instances, these do not involve any monetary transaction and therefore remain outside the GDP measure, though they are extremely important for the economy. Also, the unpaid work is done mostly by women even today, in India and across the globe.
Answer:

1. According to this paragraph the domestic work done by mainly women is not calculated under GDP and it is ignored. Women are mostly engaged in this work.
2. These services of women are not included in the GDP. The women’s work is unpaid work.
3. Woman is the nucleus of the family in India. In our country we give much importance to woman.
4. The woman in a family discharges her duties as a mother, wife and daughter in law and so on but not as an employee.
5. Employees can be paid for their work but the work of a woman in a family cannot be paid.
6. I agree with this because families depend on this work. It is not monitorial work but a work of responsibility and affection.
7. The work of the woman also can be considered as a part of GDP.
8. The economists should consider their work and calculate in GDP.
9. The work done by women at home is not worthless.

Question 15.
Read the following paragraph and write whether you agree with this or not.
It means that there are more people in agriculture but everyone may not be fully occupied.
So, even if few people move out, production will not be affected. In other words, workers in agricultural sector are underemployed.
Answer:

1. According to this paragraph there is no full employment in agriculture.
2. Partial employment is there. It means many people depend on agriculture but they are not fully employed.
3. If some of them move to another sector it will not affect the production.
4. In other words, it is called disguised unemployment. There are so many farmers like Gayathri owning about 2 or less acres of land.
5. All the five members are working in the same fields though they don’t have sufficient work.
6. My suggestion is that the government should collect data of this situation throughout the state and prepare plans to provide work by implementing programmes like MGNREGA, Watershed Development Program, Water Conservation Movement (Neeti Samrakshana Udyamam), and other activities.
7. Thus the people are engaged in some useful work and so they get sufficient work and improve their living conditions.

Question 16.
Read the following paragraph and write your opinion.
There are lakhs of farmers like Gayathri in India. This means that even if several people from agricultural sector are provided with proper work elsewhere, agricultural production will not suffer. The incomes of the people who take up other work would increase the total family income.
Answer:

1. It is explained in this paragraph that the small farmers in India have not sufficient work in the fields but they are not getting sufficient work as well as income.
2. There is a suggestion for the families like Gayathri to go elsewhere for additional work so as to earn more income.
3. Lakhs of families in India are small families having less than two acres of cultivable land.
4. All the family members depend on the small piece of land.
5. They get less work and they don’t work up to their potentials.
6. This condition is called underemployment.
7. According to my opinion the government should identify these people and plan to design various schemes to be implemented.
8. In villages many people have no sufficient work. Many developmental works are needed for villages and towns.
9. These people will be involved in that works and so they earn some income.
10. People also think to work by organizing small shops, working as repair persons, transport persons and so on.

Question 17.
Read the following paragraph and write your opinion on it.
Today, we not only have to generate new employment opportunities but also train many workers to work efficiently and with machines, We should invest in many industries, in both rural and semi-urban areas, so that we are able to produce many more goods and services. 
Answer:

1. According to this paragraph two things are very important.
2. They are providing employment opportunities and giving training to them to work with machines.
3. Without skill the workers and employees do not work efficiently.
4. One more point is that the industries are to be opened in rural and semi-urban areas to increase in production of goods and services.
5. My opinion is that it is better to provide quality and skill oriented training before generating employment to the people.
6. If skill is provided they can work at any place it demands. Many industries are being established in urban areas only.
7. Technology is bringing many changes in our daily life.
8. In agriculture, industry and service sectors technology is used.
9. Even in agriculture many machines like tractors, Combined Harvesters are there.
10. Everyone should learn how to deal with these. For that training is necessary.
11. If skill in performing jobs and access to various opportunities are provided by establishing industries in rural and semi-urban areas.

Question 18.
Observe the following table and answer the questions that follow.

Sector	Employment (%)		Gross Domestic Product (%)
	1972- 73	2009-10	1972-73	2009-10
Agriculture	74%	53%	43%	17%
Industry	11%	22%	22%	26%
Services	15%	25%	35%	57%

1. What are the major changes that you observe from the above table?
   Answer:
   There is a great shift from the agricultural sector to industrial and service sectors.
2. What is the table about?
   Answer:
   The table is about the percentage of workers employed in different sectors in India in 1972-73 and in 2009-10.
3. Which sector is providing more employment in 1972-73?
   Answer:
   Agriculture sector is providing more employment in 1972-73. It is about 74%.
4. Which sector has doubled in providing employment?
   Answer:
   The sector which has doubled in providing employment is industrial sector. 11% has become 22% from 1972-73 to 2009-10.
5. What percentage of employment is decreased in agriculture sector?
   Answer:
   21% of employment is decreased in agriculture sector. (74% – 53%)
6. Why is the employment in agriculture decreasing?
   Answer:
   The employment in agriculture is decreasing because the workers are shifting to other sectors as there is no prosperity in agriculture.

Question 19.
Observe the graph and answer the following questions.

1. What is the graph about?
   Answer:
   The graph is about GDP by agriculture, industry and service sector.
2. Which was the largest producing sector in 1972-73?
   Answer:
   Agriculture sector was the largest producing sector with Rs. 2,43,082 crore.
3. Which was the largest producing sector in 2009-10?
   Answer:
   Service sector was the largest producing sector in 2009-10 with Rs. 25,78,165 crore.
4. What is the aggregate GDP in 2009-10?
   Answer:
   The aggregate GDP in 2009-10 is Rs. 45,16, 071 crore.
5. What is the aggregate GDP in 1972-73?
   Answer:
   The aggregate GDP in 1972-73 is Rs. 5,86, 346 crore.
6. Mention any two service activities.
   Answer:
   Tailoring, courier service, etc.

Question 20.
Observe the table and answer the following questions.
Distribution of Workers in India, 2009-10 (%)

Sector	Place of Residence		Sex		All workers
	Rural	Urban	Male	Female
Agriculture Sector	68	8	47	69	53
Industry Sector	17	34	34	16	22
Services Sector	15	58	19	15	25
Total	100	100	100	100	100

1. What does this table tell us ?
   Answer:
   This table tells us about the distribution of workers in India.
2. In which sector the female workers are more ?
   Answer:
   The female workers are more in agriculture sector.
3. Which sector is prosperous in rural areas ?
   Answer:
   Agriculture sector is prosperous in rural areas.
4. Why is agriculture sector very low in urban areas ?
   Answer:
   In urban areas many people depend upon service sector and industries and there is no scope for agriculture.
5. Which sector is decreasing gradually ?
   Answer:
   Agriculture sector is decreasing gradually.
6. What have you observed in industrial sector with regard to place of residence ?
   Answer:
   Industrial sector in urban areas is double in comparison to rural areas.

Question 21.
Discuss the changes in importance of different sectors over a period of time.
Answer:

1. At the beginning as the methods of farming changed and agriculture began to prosper, it produced much more food than before.
2. After Industrial Revolution, the mass production by factories were at much lower rates and these goods reached markets all over the world.
3. So, for these countries industrial production gradually became the most important sector.
4. Hence, in overtime a shift took place.
5. In the past 50 years, there has been a further shift from industry to service sector for developed countries.
6. The service sector has become the most important in terms of total production.
7. Most of the working people also shifted and are now employed in the service sector.
8. This is the general pattern observed for developed countries.

Question 22.
Who do constitute the unorganised sector ?
Answer:

1. In the rural areas, the unorganised sector mostly comprises of landless agricultural labourers, small and marginal farmers, sharecroppers and artisans, etc.
2. In the urban areas, unorganised sector comprises mainly of workers in small-scale industry, casual workers in construction, trade and transport, etc. those who work as street vendors, head load workers, garment workers, rag pickers, etc.
3. We also find that majority of workers from scheduled castes, tribes and backward communities find themselves In the unorganised sector,
4. It is worse if one is a woman from these communities,
5. Besides getting the irregular and low paid work, these workers also face social discrimination.

Question 23.
Locate the following in the given map of India.

1. The monsoons first enter into India into this state.
   Answer:
   Kerala
2. Locate the Jammu Hills.
   Answer: Jammu
3. The dun which is in Uttarakhand.
   Answer: Patli Dun
4. The wettest place in India.
   Answer: Mawsynram
5. The Great Indian Desert.
   Answer: Thar desert
6. The submerged point of Andaman and Nicobar Islands.
   Answer: Indira Point,
7. The capital of Andhra Pradesh.
   Answer: Amaravathi
8. The second largest river in South India.
   Answer: Krishna
9. Mahadev hills.
10. Maikal plateau.

AP State Board Syllabus AP SSC 10th Class Chemistry Solutions Chapter 4 Acids, Bases and Salts Textbook Questions and Answers.

AP State Syllabus SSC 10th Class Chemistry Solutions 4th Lesson Acids, Bases and Salts

10th Class Chemistry 4th Lesson Acids, Bases and Salts Textbook Questions and Answers

Review of Your Previous Knowledge

Question 1.
Which property do you think of while suggesting the remedy from a problem of acidity?
Answer:
Neutralization Property. Antacid tablets neutralise acidity.

Improve your learning

Question 1.
Five solutions A, B, C, D and E when tested with universal indicator showed pH as 4, 1, 11,7 and 9 respectively, which solution is : (AS1)
a) neutral
b) strongly alkaline
c) strongly acidic
d) weakly acidic
e) weakly alkaline
Arrange the pH in increasing order of hydrogen ion concentration.
Answer:
Solution – pH Value
A → 4
B → 1
C → 11
D → 7
E → 9
a) Solution ‘D’ is neutral
b) Solution ‘C’ is strongly alkaline
c) Solution ‘B’ is strongly acidic
d) Solution ‘A’ is weakly acidic
e) Solution ‘E1 is weakly alkaline
∴ Increasing order of Hydrogen ion concentration : C < E < D < A < B.

Question 2.
What is a neutralization reaction? Give two examples. (AS1)
Answer:
Neutralization reaction : When acid reacts with base, forms its salt and water. This reaction is called a neutralization reaction.
Examples :

Equation: HCl + NaOH → NaCl + H₂O
ii) Acetic Acid + Sodium Hydroxide → Sodium Acetate + Water
Equation : CH₃COOH + NaOH → CH₃COONa + H₂O
Formula : Acid + Base > Salt + Water

Question 3.
What happens when an acid or base is mixed with water? (AS1)
Answer:
When an acid or base is mixed with water it changes into dilute acid or dilute base.
(OR)
Dilute acid or dilute base will be formed when an acid or base is mixed with water. Mixing an acid or base with water results in decrease in the concentration of ions (H30+/ OH-) per unit volume. Such a process is called dilution and the acid or base is said to be diluted.

Question 4.
Why does tooth decay start when the pH of mouth is lower than 5.5? (AS1)
(OR)
Does the pH change tooth decay? Explain.
Answer:

1. Tooth enamel is the hardest substance in the body.
2.  It doesn’t dissolve in water but corroded when the pH in the mouth is below 5.5.
3. It happens due to the bacteria which produce acids by degradation of sugar and food particles remaining in the mouth.

Question 5.
Why does not distilled water conduct electricit? (AS2)
Answer:

1. Distilled water does not contain impurities.
2. It is also extremely weak electrolyte.
3. So it does not dissociate into ions.
4. It does not have charge carriers.
5. Because of that it does not conduct electricity.

Question 6.
Dry hydrogen chloride gas does not turn blue litmus to red whereas hydrochloric acid does. Why? (AS1)
Answer:
1. Dry hydrogen chloride gas is not an acid. Because it does not produce H⁺_(aq) ions. Hence it can’t turn blue litmus into red.
2. Hydrochloric acid is an aqueous solution. So it can produce H⁺_(aq) ions. Hence it can turn blue litmus into red.

Question 7.
Why pure acetic acid does not conduct electricity? (AS1)
Answer:
The reasons for pure acetic acid does not conduct electricity are :
i) Acetic acid is a weak acid.
ii) It gives fewer H₃O⁺ ions.

Question 8.
A milkman adds a very small amount of baking soda to fresh milk. (AS2)
a) Why does he shift the pH of the fresh milk from 6 to slightly alkaline?
Answer:
1. By adding a very small amount of baking soda to fresh milk, the milkman keeps the milk unspoiled for little more time than usual time.
2. As the pH value increases the milk turns to slightly alkaline.

b) Why does this milk take a long time to set as curd?
Answer:

1. Curd form from the milk by the action of Lactic acid produced by bacteria in the milk.
2. If milk man add Baking soda (NaHCO₃) to the milk it neutralise acid, which is produced by the bacteria.
3. Excess acid is required to change the milk as curd.
4.  It takes long time.

Question 9.
Plaster of Paris should be stored in a moisture-proof container. Explain why? (AS2)
Answer:
Storing of Plaster of Paris :

1. Plaster of Paris is a white powder.
2. It easily absorbs water in air and forms hard gypsum.
3. So, it should be stored in a moisture-proof container.

Question 10.
Fresh milk has a pH of 6. Explain why the pH changes as it turns into curd.
Answer:
1. Fresh milk has a pH of 6. Hence it is a weak acid.
2. To turn the milk as curd, we have to add yeast in the form of some curd. The fermentation takes place during this process and lactose changes in lactic acid and the pH decreases as milk sets as curd.

Question 11.
Compounds such as alcohols and glucose contain hydrogen but are not categorized as acids. Describe an activity to prove it. (AS3)
(OR) (Activity – 7)
Write an activity to show that the solutions of compounds like alcohol and glucose do not show acidic character even though they are having Hydrogen.
(OR)
Write an activity which proves acids are good conductors of electricity.
(OR)
The acidity of acids is attributed to the H+ ions produced by them in solution explain the above statement with an activity.
List out the material for the experiment to investigate whether all compounds containing Hydrogen are acids or not and write the experimental procedure.
Answer:
List of the material required :

1. Glucose
2. Alcohol
3. Dil. HCl
4. Dil-H₂SO₄
5. Beaker
6. Connecting wires
7. 230 voltage AC supply
8. Bulb
9. Graphite rods.

Procedure :

1. Prepare glucose, alcohol, hydrochloric acid and sulphuric acid solutions.
2. Connect two different coloured electrical wires to graphite rods separately as shown in figure.
3. Connect free ends of the wire to 230 volts AC plug.
4. Complete the circuit as shown in the figure by connecting a bulb to one of the wires.
5. Now pour some dilute HCl in the beaker and switch on the current.

Observation :
The bulb starts glowing.

Repetition:
Repeat activity with dilute sulphuric acid, glucose and alcohol solutions separately.

Observation :

1. We will notice that the bulb glows only in acid solutions.
2. But the bulb does not glow in glucose and alcohol solutions.

Result:

1. Glowing of bulb indicates that there is flow of electric current through the solution.
2. Acid solutions have ions and the movement of these ions in solution helps for flow of electric current through the solution.

Conclusion :

1. The positive ion (cation) present in HCl solution is H⁺.
2. This suggests that acids produce hydrogen ions H⁺ in solution, which are, responsible for their acidic properties.
3. In glucose and alcohol solution the bulb did not glow indicating the absence of H⁺ ions in these solutions.
4. The acidity of acids is attributed to the H⁺ ions produced by them in solutions.

Question 12.
What is meant by “water of crystallization” of a substance? Describe an activity to show the water of crystallisation. (Activity – 16) (AS3)
Answer:
Water of Crystallization : Water of crystallization is the fixed number of water molecules present in one formula unit of a salt in its crystaline form.
Ex : CuSO₄ • 5H₂O.
It means that five water molecules are present in one formula unit of copper sulphate.

Activity to show the water of crystallization :

1. Take a few crystals of copper sulphate in a dry test tube and heat the test tube.
2. We observe water droplets on the walls of the test tube and salt turns white.
3. Add 2 – 3 drops of water on the sample of copper sulphate obtained after heating.
4. We observe, the blue colour of copper sulphate crystals is restored.

Reason :
1. In the above activity copper sulphate crystals which seem to be dry contain the water of crystallization, when these crystals are heated, water present in crystals is evaporated and the salt turns white.

2. When the crystals are moistened with water, the blue colour reappears.
Removing water of crystallization

Question 13.
Equal lengths of magnesium ribbons are taken in test tubes A and B. Hydrochloric acid is added to test tube A, while acetic acid is added to test tube B. Amount and concentration of both the acids are same. In which test tube will the fizzing occur more vigorously and why? (AS4)
Answer:
1. The volatility of acetic acid (CH₃COOH) is more than that of hydrochloric acid.
2. But HCl solution has more strength than acetic acid.
3. Hence magnesium ribbon in test tube A will react more vigorously than in B.
4. So fizzing occurs more vigorously in test tube ‘A’.

Question 14.
Draw a neat diagram showing acid solution in water conducts electricity. (AS5)
(OR)
Draw a neat diagram which shows acids contains H⁺ ions.
(OR)
Draw a neat diagram showing how does dilute HCl solution conduct electricity.
Answer:

Question 15.
How do you prepare your own indicator using beetroot ? Explain. (AS5)
Aim : To prepare own indicator.
Materials required :
1) Beetroots-2 or 3
2) Knife
3) Bowls
4) Water
5) Spoon
6) Mixy
7) Orange juice

Procedure:
1) Take the beetroots and peel them with the help of a knife. (Firstly wash them).
2) Chop them into pieces.
3) Put those pieces into a mixy jar and make a paste.
4) Add some water to the paste. Now filter this and collect only juice from this.

Observation and Result:
1) Now add 5 to 6 drops of this juice, (beetroot juice (indicator)) to orange juice (5 to 6 drops) and mix it.
2) We can see the colour changes. This indicates the presence of acidic nature in orange juice.

Question 16.
How does the flow of acid rain into a river make the survival of aquatic life in a river difficult? (AS7)
(OR)
What are the harmful effects of acid rain?
Answer:
1) Acid rains are combination of carbonic acid, sulphuric acid and nitric acid with rain water.
2) The pH of acid rain is less than 5.6.
3) Living organisms can survive only in a narrow range of pH change.
4) When acid rain with pH value less than 5.6, flows into rivers, it lowers the pH of river water.
5) Due to less pH, the river water becomes acidic and hence the aquatic life in such rivers becomes difficult.

Question 17.
What is baking powder? How does it make the cake soft and spongy? (AS7)
Answer:
1) Baking Powder:
Baking powder is a mixture of baking soda (NaHCO₃) and a mild edible acid such as tartaric acid. COOH (CHOH)₂ COOH

2) Chemical reaction :
When baking powder is heated or mixed in water, the following reaction takes place.
NaHCO₃ + H⁺ → CO₂ + H₂O + Sodium salt of acid.

3) Carbondioxide produced during the reaction causes bread or cake to rise making them soft and spongy.

Question 18.
Give two important uses of washing soda and baking soda. (AS7)
(OR)
Write the chemical formulae for washing soda and Baking soda and give their uses.
(OR)
Write any four uses of washing soda.
Answer:
Uses of washing soda (Na₂CO₃.10H₂O) :
1) Washing soda (sodium carbonate) is used in glass, soap and paper industries.
2) It is used in the manufacture of sodium compounds such as borax.
3) Sodium carbonate can be used as a cleaning agent for domestic purposes.
4) It is used for removing permanent hardness of water.

Uses of baking soda (NaHCO₃ 10H₂O) :
1) Baking soda (Sodium hydrogen carbonate) is used for faster cooking.
2) Baking powder (a mixture of baking soda and a mild acid) is used in preparation of cakes.
3) Sodium hydrogen carbonate is also an ingredient in antacids.
4) It is also used in soda – acid, fire extinguishers.
5) It acts as a mild antiseptic.

Fill in the Blanks

1. i) ………………….. taste is a characteristic property of all acids in aqueous solution.
ii) Acids react with some metals to produce ………………….. gas.
iii) Because aqueous acid solutions conduct electricity, they are identified as …………………..
iv) Acids react with bases to produce a ………………….. and water.
v) Acids turn methyle orange into ………………….. colour.
Answer:
1. i) Sour
ii) hydrogen
iii) electrolytes or conductors
iv) salt
v) red

2. i) Bases tend to taste ………………….. and feel ………………….. .
ii) Like acids, aqueous basic solutions conduct ………………….., and are identified as ………………….. .
iii) Bases react with ………………….. to produce a salt and
iv) Bases turn phenophthalein into ………………….. colour.
Answer:
2. i) bitter, soapy (slippery) to touch
ii) electricity, electrolytes
iii) acids, water
iv) pink

Match the following :

a) Plaster of Paris	1) CaOCl2
b) Gypsum	2) NaHCO3
c) Bleaching powder	3) Na2CO3
d) Baking soda	4) CaSO4.½H2O
e) Washing soda	5) CaSO4.2H2O

Answer:
3. a – 4,
b – 5,
c – 1,
d – 2,
e – 3.

Multiple Choice Questions

1. The colour of methyl orange indicator in acidic medium is
A) yellow
B) green
C) orange
D) red
Answer:
D) red

2. The colour of phenolphthalein indicator in basic solution is
A) yellow
B) green
C) pink
D) orange
Answer:
C) pink

3. Colour of methyl orange in alkali conditions
A) orange
B) yellow
C) red
D) blue
Answer:
B) yellow

4. A solution turns red litmus blue, its pH is likely to be
A) 1
B) 4
C) 5
D) 10
(OR)
If a solution converts red litmus into blue colour, then its pH value is …………….. .
A) 1
B) 4
C) 5
D) 10
Answer:
D) 10

5. A solution reacts with crushed egg-shells to give a gas that turns lime-water milky, the solution contains …………….. .
A) NaCl
B) HCl
C) LiCl
D) KCl
Answer:
B) HCl

6. If a base dissolves in water, by what name is it better known?
A) neutralization
B) basic
C) acid
D) alkali
Answer:
D) alkali

7. Which of the following substances when mixed together will produce table salt?
A) Sodium thiosulphate and sulphur dioxide
B) Hydrochloric acid and sodium hydroxide
C) Chlorine and oxygen
D) Nitric acid and sodium hydrogen carbonate
Answer:
B) Hydrochloric acid and sodium hydroxide

8. What colour would hydrochloric acid (pH = 1) turn universal indicator?
A) Orange
B) Purple
C) Yellow
D) Red
Answer:
D) Red

9. Which one of the following types of medicines is used for treating indigestion?
A) antibiotic
B) analgesic
C) antacid
D) antiseptic
Answer:
C) antacid

10. What gas is produced when magnesium is made to react with hydrochloric acid?
A) hydrogen
B) oxygen
C) carbon dioxide
D) no gas is produced
Answer:
A) hydrogen

11. Which of the following is the most accurate way of showing neutralization?
A) Acid + base → acid-base solution
B) Acid + base → salt + water
C) Acid + base → sodium chloride + hydrogen
D) Acid + base → neutral solution
Answer:
B) Acid + base → salt + water

10th Class Chemistry 1st Lesson Acids, Bases and Salts InText Questions and Answers

10th Class Chemistry Textbook Page No. 25

Question 1.
Is the substance present in antacid tablet acidic or basic?
A. The substance present in antacid tablet is basic.

Question 2.
What type of reaction takes place in stomach when an antacid tablet is consumed?
mrearx
A. Neutralization reaction takes place in stomach when an antacid tablet is consumed.

10th Class Chemistry Textbook Page No. 26

Question 3.
You are provided with three test tubes containing distilled water, an acid and a base solution respectively. If you are given only blue litmus paper, how do you identify the contents of each test tube?
Answer:
I know that acid turns blue litmus to red. With the help of this test I can find the acid. Distilled water and base don’t do so. Thus I identify each.

Question 4.
Which gas is usually liberated when an acid reacts with a metal? How will you test for the presence of this gas?
Answer:
Usually acids generate hydrogen gas on reacting with metals.

Test: When a burning splinder is brought near to the collected gas (H₂), it puts off with a pop sound.
This test proves that the gas is H₂.

Question 5.
A compound of a calcium reacts with dilute hydrochloric acid to produce effervescence. The gas evolved extinguishes a burning candle ; turns lime water milky. Write a balanced chemical equation for the reaction if one of the compounds formed is calcium chloride.
Answer:
Equation is : CaCO₃ + 2 HCl → CaCl₂ + CO₂ + H₂O

10th Class Chemistry Textbook Page No. 30

Question 6.
Why do HCl, HNO₂ etc. show acidic characters in aqueous solutions while solutions of compounds like alcohol and glucose do not show acidic character?
Answer:
HCl, HNO₃, etc. show acidic characters in aqueous solutions as they liberate H⁺ ions. But alcohol and glucose don’t liberate H⁺ ions. So, they do not show acidic character.

Question 7.
While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid?
Answer:
1) If water is added to a concentrated acid, the heat generated may cause the mixture to splash out and cause burns.
2) The glass container may also break due to excessive local heating.

10th Class Chemistry Textbook Page No. 33

Question 8.
What will happen if the pH value of chemicals in our body increases?
Answer:
When pH value of chemicals in our body increases then the body will effect by some problems. They are
1) Digestion problems raise in the stomach.
2) pH changes as the cause of tooth decay.

Question 9.
Why do living organism have narrow pH range?
Answer:
Because increasing acidity is thought to have a range of possibly harmful consequences such as depressing metabolic rate and immune response in some organisms and causing coral bleaching

10th Class Chemistry 4th Lesson Acids, Bases and Salts Activities

Activity – 1

Question 1.
Observe the change in colour in each case and tabulate the results in the table.
Answer:
Procedure:
1) Collect the following samples from the science laboratory ;
i) Hydrochloric acid (HCl)
ii)Sulphuric acid (H₂SO₄)
iii) Nitric acid (HNO₃)
iv) Acetic acid (CH₃COOH)
v) Sodium hydroxide (NaOH)
vi) Calcium hydroxide[Ca(OH)₂]
vii) Magnesium hydroxide [Mg(OH)₂]
viii) Ammonium hydroxide(NH₄OH)
ix) Potassium hydroxide (KOH)
2) Prepare dilute solutions of the respective substances.
3) Take four watch glasses.
4) Put one drop of the first solution in each one of them and test the solution as follows.
i) Dip the blue litmus paper in the first watch glass.
ii) Dip the red litmus paper in the second watch glass.
iii) Add a drop of methyl orange to the third watch glass.
iv) Add a drop of phenolphthalein to the fourth watch glass.

Observation :
Observe the respective colour changes and note down in the chart below.

1. What do you conclude from the observations noted in the above table? (AS1)
Answer:
Conclusion : Acids turn blue litmus to red and bases turn red litmus to blue. Acids turn phenolphthalein to colourless and bases turn pink. Acids turn methyl orange to red and bases turn methyl orange to yellow.

2. Identify the above sample as acidic or basic solution. (AS4)
Answer:
Acids : HCl, H₂SO₄, HNO₃, CH₃COOH.
Bases : NaOH, KOH, Mg(OH)₂, NH₄OH, Ca(OH)₂.

Activity -2

Question 2.
What are Olfactory indicators? Write an activity to prove them.
(OR)
What is the name given to a substance which identifies an acid or base by virtue of smell? Write an activity to prove the fact with an example.
Answer:
Olfactory Indicators : There are some substances whose odour changes in acidic or basic media. These are called olfactory indicators.
Activity :
Aim : To check the olfactory indicator.
Required materials :
1) Onions
2) Knife
3) Plastic bag
4) Clean clothes.

Procedure :
1) Take some onions and finely chop them.
2) Put the chopped onions in a plastic bag along with some clean cloth.
3) Tie up the bag tightly and keep it overnight in the fridge.
4) Then remove onions from fridge and add some base. We observe it loses its smell. Observation : Check the odour of the cloth strips.

Result: It is used as the basic indicator.

LAB ACTIVITY Reaction of Acids with metals

Question 3.
Write an experiment showing the reaction of acids with metals. (AS3)
(OR)
Ramu added acid to active metal then what is the gas which has been liberated. What are the apparatus required to prove the experiment. Write the experimental acitivity.
(OR)
Write the required material and experimental procedure for the experiment, “Hydrochloric acid reacts with ‘Zn’ pieces and liberates H₂“.
Answer:
Aim : To show the reaction of acids with metals.

Required Materials :

1. Test tube
2. Delivery tube
3. Glass trough
4. Candle,
5. Soap water
6. Dil. HCl
7. Zinc granules
8. One holed rubber stopper
9. Retard stand

Experimental procedure :

1. Take some zinc granules in a test tube and arrange the test tube to the retart stand.
2. Fix a delivery tube to the rubber stopper and immerse the second end of the delivery tube into the soap water.
3. Add about 10 m/ of dilute hydrochloric acid to Zn granules and fix rubber stopper to the test tube.
4. Evolved gas forms bubbles in soap water.
5. Bring a lightened candle near to the gas bubbles. We can observe the burning of gas bubble with pop sound.

Result: We can conform that the evolved gas is hydrogen.
Chemical reaction:
Acid + Metal → Salt + Hydrogen
2Hcl_(aq) + Zn_(s) → Zncl_2(aq) + H_2(g)

Additional Experiment :

• Repeat the above experiment with H₂SO₄ and HNO₃.
• We observe the same observation of the HCL experiment.

Conclusion : From the above activities we can conclude that when acid reacts with metal, H₂ gas is evolved.

Activity – 3 Reaction of Bases with metals

Question 4.
Write an activity to show the reaction of bases with metals.
(OR)
Write an activity which proves certain bases produce hydrogen gas when they react with metals.
Answer:
Aim : To show the reaction of bases with metals.

Required Materials :

1. Test tube,
2. Delivery tube
3. Glass trough
4. Candle
5. Soap water
6. Sodium hydroxide (NaOH) Solution
7. Zinc granules
8. One holed rubber stopper

Procedure :

1. Set the apparatus as shown in figure.
2. Take about 10 ml of dilute Sodium hydroxide (NaOH) solution in a test tube.
3. Add a few granules of zinc metal to it.
4. We will observe formation of gas bubbles on the surface of granules.
5. The gas will pass through delivery tube evolved from soap solution as bubbles.
6. Bring burning candle near the gas filled bubble.
7. The gas in the bubble puts off the candle with pop sound.

Result: The evolved gas is hydrogen.

Chemical reaction :
Base + Metal → Salt + Hydrogen

Note : It is better to use cone. NaOH solution for this reaction.

Activity – 4 Reaction of carbonates and metal hydrogen carbonates with Acids

Question 5.
Write an activity to show that all metal carbonates and hydrogen carbonates react with acids to give a corresponding salt. (AS3)
Answer:
Aim : To show that all metal carbonates and hydrogen carbonates react with acids to give a corresponding salt.

Required Materials :

1. Two test tubes
2. Sodium Carbonate (Na₂CO₃)
3. Sodium Hydrogen Carbonate (NaHCO₃)
4. Two holed rubber stopper
5. Thistle funnel
6. Stand
7. Dilute hydrochloric acid
8. Delivery tube
9. Calcium Carbonate (in a test tube)

Procedure :

1. Take a test tube A with 0.5 gm of sodium carbonate.
2. Close the test tube A with two holed rubber cork.
3. Insert a thistle funnel through one hole and insert a delivery tube through the other hole.
4. Pour 2 ml of dilute HC/ to the test tube A.
5. Do the same as above with test tube B with sodium hydrogen carbonate.

Observation :
Carbon dioxide is released from test tube A and B. Passing CO₂ gas through Ca(OH)₂ solution

Chemical Reaction :
Na₂CO_3(s) + 2 HCl_(aq) → 2 NaCl_(aq) + CO_2(g) + H₂O_(l)
Metal Carbonate + Acid → Salt + Carbon dioxide + Water

NaHCO_3(s) + HCl_(aq) → NaCl_(aq) + CO_2(g) + H₂O_(l)
Metal Hydrogen Carbonate + Acid → Salt + Carbon dioxide + Water

Result : All metal carbonates and hydrogen carbonates react with acids to give a corresponding salt.

Activity – 5 Neutralization reaction

Question 6.
Write an activity to find the change of colour in the reaction of an acid with a base (Neutralization) reaction. (AS3)
(OR)
Explain neutralization reaction with an activity.
Answer:
Aim : To test the change of colour in the reaction of an acid with a base.

Required Materials :

1. 2 ml of dilute NaOH (Sodium Hydroxide) solution.
2. Phenolphthalein indicator solution.
3. dilute HCl (Hydrochloric) solution.

Procedure :

1. Take about 2 ml of dilute NaOH solution in a test tube.
2. Add two drops of phenolphthalein indicator solution.

Observation (i) :

1. It turns to red or pink colour.
2. It shows that NaOH is a base.

Experiment (1) : Add dilute HCl solution to the above solution drop by drop.
Observation (ii) : Pink colour disappears due to the reaction of NaOH (base) with HCl (acid).

Experiment (2) : Now add one or two drops of NaOH to the above mixture.
Observation (iii) : Pink colour reappears on adding NaOH.
NaOH + HCl → NaCl + H₂O
base + acid → salt + water
Result: This reaction is called a neutralization reaction.

Activity – 6 Reaction of metallic oxides with acids

Question 7.
Write an activity to show that metal oxide reacts with acid is a neutralization. (AS3)
(OR)
How can you prove metallic acids are basic in nature?
Answer:
1) Take a small amount of copper oxide (CuO) in a beaker.
2) Add dilute HCl slowly while stirring.
3) Copper oxide dissolves in dilute HCl and the solution becomes blueish green colour due to the formation of copper (II) chloride.

Equation : Metal oxide + Acid → Salt + Water
Result: This reaction is same as the reaction of base with acid, (neutralization)

Question 8.
Write an activity to show that non-metallic oxide reacts with base is a neutralization.
Answer:
1) Take a small amount of calcium hydroxide (base).
2) Add CO₂ into it.
3) Salt and water are produced.
Equation : Non-metallic oxide + Base → Salt + Water
Result: It is a neutralization reaction.

Question 9.
Repeat the activity – 7 using alkalis such as sodium hydroxide, calcium hydroxide solutions, etc. instead of acid solutions.
i) Does the bulb glow?
Answer:
Yes, the bulb will glow.

ii) What do you conclude from the results of this activity?
Answer:
Basic solutions are also good conductors of electricity due to released OH^– ions.

iii) What happens to an acid or a base in aqueous solution?
Answer:
Acids produce H⁺ ions and bases produce OH^– ions in aqueous solutions.

iv) Do acids produce ions only in aqueous solution?
Answer:
Yes.

Activity – 8

Question 10.
Do acids produce ions only in aqueous solution? Prove it. (AS3)
(OR)
Acids produce ions only in aqueous solution. Justify your answer with an activity.
Answer:
Procedure :

1. Take about 1.0 g of solid NaCl in a clean and dry test tube.
2. Add some concentrated sulphuric acid to the test tube. .

Observation :

1. A gas comes out of the delivery tube.
2. If we test the gas with dry and wet blue litmus paper, there is no change in colour.

Chemical equation : 2 NaCl_(s) + H₂SO_4(l) > 2 HCl + Na₂SO_4(s)

Conclusion :

1. We can conclude that dry HCl gas (hydrogen chloride) is not an acid.
2. Because we have noticed that there is no change in colour of dry litmus paper.
3. But HCl aqueous solution is an acid because wet blue litmus paper turned into red.

Activity – 9 Reaction of water with acids or bases

Question 11.
Write an activity to show that dissolving of an acid in water is an exothermic process (or) endothermic process. (AS3)
(OR)
What do you observe when water is mixed with acid or base?
Answer:
Experiment :

1. Take 10 ml water in a beaker.
2. Add a few drops of concentrated H₂SO₄ to it and swirl the beaker slowly.
3. Touch the base of the beaker.
4. The base is hot.
5. Do this experiment with other concentrated acids like HCl, HNO₃ Result: This is an exothermic process called dilution.

Activity -10 Strength of acid or base

Question 12.
Write an activity to know whether the acid is strong or weak. (AS3)
Answer:

1. Take dilute HCl in a beaker.
2. Close it with a cardboard and introduce two different colour electrical wires through the holes made on it.
3. Connect a bulb and make the connection as shown in the figure.
4. Do the same replacing dilute HCl with dilute CH₃COOH (acetic acid).

Observation :
The bulb glows brightly in HCl solution, while the bulb’s intensity is low in acetic acid solution.

Result:
More ions are present in HCl solution which is a strong acid than in CH₃COOH solution which is a weak acid.

Activity – 11

Question 13.
Test the pH value of solution given in table. Record your observations. What is the nature of each substance on the basis of your observations?
Answer:

Activity – 12

Question 14.
Write an activity to check the colour change in dilute HCl and antacid solution in addition of methyl orange. (AS3)
Answer:
Procedure :

1. Take dilute HCl in a beaker.
2. Add two to three drops of methyl orange indicator to it.
3. The solution colour turns to red.
4. Now take the same solution and mix antacid tablet powder.

Observation :
Check the colour change.

Result:
The colour of the solution turns to light yellow.

Chemical equation:
2 HCl + Mg(OH)₂ → MgCl₂ + 2H₂O

Activity – 13

Question 15.
How can we test the pH value of the soil? (AS3)
Answer:

1. Take about 2g of soil in a test tube.
2. Add 5 ml water to it.
3. Shake it well.
4. Filter the content.
5. Collect the filtrate in a test tube.
6. Add 2 drops of universal solution to it.
7. Observe the colour.
8. Compare the colour with strip colour on the bottle and find the pH value.
9. In this way we can test the pH of the soil.

Activity – 14

Question 16.
Write the formulae of the following salts and classify them as families based on radicals.
Potassium Sulphate, Sodium Sulphate, Calcium Sulphate, Magnesium Sulphate, Copper Sulphate, Sodium Chloride, Sodium Nitrate, Sodium Carbonate and Ammonium Chloride. (AS4)
Answer:

Name of the Salt	Formula
1. Potassium Sulphate	K2SO4
2. Sodium Sulphate	Na2SO4
3. Calcium Sulphate	CaSO4
4. Magnesium Sulphate	MgSO4
5. Copper Sulphate	CuSO4
6. Sodium Chloride	NaCl
7. Sodium Nitrate	NaNO3
8. Sodium Carbonate	Na2CO3
9. Ammonium Chloride	NH4Cl

Sodium family : Na₂SO₄, NaCl, NaNO₃, Na₂CO₃, etc.
Family of chloride salts : NaCl, NH₄Cl, etc.
Family of sulphate salts : K₂SO₄, Na₂SO₄, CaSO₄, MgSO₄, CuSO₄, etc.
Family of carbonate salts : Na₂CO₃ MgCO₃ CaCO₃, etc.

Question 17.
Identify the acids and bases from which they are obtained. (AS4)
Answer:

Name of the Salt	Parent Acid	Parent Base
1. Potassium Sulphate	Sulphuric Acid	Potassium Hydroxide
2. Sodium Sulphate	Sulphuric Acid	Sodium Hydroxide
3. Calcium Sulphate	Sulphuric Acid	Calcium Carbonate
4. Magnesium Sulphate	Sulphuric Acid	Magnesium Hydroxide
5. Copper Sulphate	Sulphuric Acid	Copper Hydroxide
6. Sodium Chloride	Hydrochloric Acid	Sodium Hydroxide
7. Sodium Nitrate	Nitric Acid	Sodium Hydroxide
8. Sodium Carbonate	Carbonic Acid	Sodium Hydroxide
9. Ammonium Chloride	Hydrochloric Acid	Ammonium Hydroxide

Activity – 15 pH of Salts

Question 18.
Collect the salt samples like sodium chloride, aluminium chloride, copper sulphate, sodium acetate, ammonium chloride, sodium hydrogen carbonate and sodium carbonate. Dissolve them in distilled water. Check the action of these solutions with litmus papers. Find the pH using pH paper (universal indicator. Classify them into acidic, basic or neutral salts. Identify the acid and base used to form the above salts. Record your observations in table. (AS4)
Answer:

Salt	pH	Acid	Base	Neutral
Sodium Chloride	7	–	–	✓
Aluminium Chloride	7	–	–	✓
Copper Sulphate	< 7	✓	–	–
Sodium Acetate	> 7	–	✓	–
Ammonium Chloride	< 7	✓	–	–
Ammonium Chloride	> 7	–	✓	–
Sodium Carbonate	> 7	–	✓	–

 

These AP 10th Class Social Studies Important Questions 2nd Lesson Ideas of Development will help students prepare well for the exams.

AP State Syllabus 10th Class Social 2nd Lesson Important Questions and Answers Ideas of Development

10th Class Social 2nd Lesson Ideas of Development 1 Mark Important Questions and Answers

Question 1.
State reason for protesting against the establishment of Kudankulam Nuclear Power Project in Tamil Nadu.
Answer:

1. Kudankulam people have protested on the grounds of safety, security and livelihood.
2. They also want their coast and country protected from the radio active peril.

Question 2.
Why did the people oppose the establishment of Kudankulam Nuclear Power project in Tamil Nadu?
Answer:
On the grounds of safety, security and livelihood, the people protested against the project.
(OR)
To protect their cost from radio active peril people opposed it.

Question 3.
Observe the following table and answer the questions a, b, c and d.
Answer:

Country	H.D.I. Ranking 2012	Average Life Span in 2012	Average years of Schooling
Norway	1	81.3	12.6
America	3	78.7	13.3
Sri Lanka	92	75.1	9.3
China	101	73.7	7.5
India	136	65.8	4.4
Bangladesh	146	69.2	4.8
Pakistan	146	65.7	4.9
World Average	–	70.1	7.5

a) Which two countries have more average schooling years?
Answer:
Norway, America.

b) Which two Asian countries have better HDI rank than that of India?
Answer:
Srilanka, China.

c) Which countries are lacking behind to the average life expectancy of World?
Answer:
India, Bangladesh, Pakistan.

d) What are the reasons for having less average schooling in India, Bangladesh and Pakistan?
Answer:
The reasons for having less average schooling in India, Bangladesh and Pakistan are

1. Poverty,
2. More rural population,
3. No awareness with regard to literacy.

Question 4.
In the context of development, two persons or groups of persons may seek things which are conflicting. Give one example for this.
Answer:
Example – 1: To get more electricity industrialists may want more dams. But this may submerge the land and disrupt the lives of people such as the tribals who are dis-placed.
Example – 2: A girl expects as much freedom and opportunity as her brother and that he also shares in the household work. But brother may not like this.

Question 5.
What idea is the poster promoting?

Answer:
Importance of Education.

Question 6.
State any two goals of development other than income.
Answer:
Equal treatment, freedom, security and respect from others.

Question 7.
What is HDI?
Answer:
The index developed for comparing coun¬tries for measuring human development is called HDI (Human Development Index). It generally includes income, educational levels and health status of the people.

Question 8.
What is per capita income?
Answer:
Per capita income is “the total income of the country divided by its total population”.

Question 9.
Expand IMR.
Answer:
Infant Mortality Rate.

Question 10.
Which organization publishes HDR?
Answer:
UNDP publishes Human Development Report.

Question 11.
What is the main criteria for comparing the development of different countries?
Answer:
The main criteria for comparing the development of different countries are per capita income, life expectancy, average years of schooling, expected years of schooling, etc.

Question 12.
What is health?
Answer:
Health means a state of couple soundness – physical and mental.

Question 13.
Why do people look at a mix of goals?
Answer:
People look at a mix of goals for development.

Question 14.
Why are dams opposed?
Answer:
Dams are opposed because they will disrupt the lives of the people and submerge their own lands.

Question 15.
How are the women who work outside the homes?
Answer:
Women who work outside the homes are economically independent and self¬confident.

Question 16.
What is adult literacy rate?
Answer:
The rate of percentage of people aged 15 and above, who can understand, read and write a short and simple statement in their regional languages is known as adult literacy rate.

Question 17.
What is the main criterion for comparing the development of different countries?
Answer:
Average income is the main criterion for comparing the development of different countries.

Question 18.
Explain the calculation of BMI.
Answer:
BMI can be calculated by dividing the total weight of a person by the square of his height.

Question 19.
What is educational development?
Answer:
Education attained by the people of a country on an average basis is referred as educational development.

Question 20.
What isthe percentage of population living in the rural India?
Answer:
70% of the Indian population is living in rural India.

Question 21.
What is Infant Mortality Rate?
Answer:
The rate at which children in a country die within an age of 0-1 year is known as “Infant Mortality Rate.”

Question 22.
What are the factors of production?
Answer:
Land, Labour, Capital and Enterprise are the four factors of production.
Technology is also added to the factors of production.

Question 23.
How is the standard of living measured?
Answer:
Standard of living is measured by real GDP per capita.

Question 24.
What is development?
Answer:
Development refers to progress or improvement in lifestyle.

Question 25.
What is PDS?
Answer:
PDS is a system to distribute ration to the poor at a reasonable rate through govern¬ment ration shops. PDS – Public Distribution System.

Question 26.
A girl from a rich urban family has some development goals for her. State any one such goal.
Answer:
She can get as much freedom as a boy has.

Question 27.
Write any one advantage of public facilities.
Answer:
It develops national feelings and a sense of collective responsibility. Reduces expenditure.

Question 28.
What is NAR?
Answer:
Net Attendance Rate: Out of the total num¬ber of children in age group 6-17, the per¬centage of children attending schools.

Question 29.
Which is considered to be one of the most important attributes for comparing coun¬tries?
Answer:
Income is considered to be one of the most important attributes for comparing countries.

Question 30.
Which is not a useful measure for comparison between countries?
Answer:
Total income is not such a useful measure for comparison between countries.

Question 31.
What are called developed countries?
Answer:
The rich countries, excluding countries of West Asia and certain other small countries, are generally called developed countries.

Question 32.
Why, in some areas, children, particularly girls are not able to achieve secondary level schooling?
Answer:
Due to social restrictions imposed on girl child i.e., gender bias.

Question 33.
Why have some states lesser Infant Mortality Rate?
Answer:
Some states have a lesser Infant Mortality Rate because they have adequate provision of basic health and educational facilities.

Question 34.
What is the major consideration of Himachali women?
Answer:
One major consideration is that many Himachali women are themselves employed outside the home and hence show lesser gender bias.

Question 35.
How are the women who work outside the homes?
Answer:
Women who work outside the home are economically independent and self-confident.

10th Class Social 1st Lesson India: Relief Features 2 Marks Important Questions and Answers

Question 1.
What do you learn from the schooling revolution in Himachal Pradesh?
Answer:

1. Both the government and the people of Himachal Pradesh were keen on education.
2. They started many schools.
3. They made sure that education was largely free.
4. They allocated a good share to education in the government budget.
5. They tried to ensure that the schools had all the facilities.
6. Most of the students enjoy their schooling experience.

Question 2.
People generally do not like to work in unorganised sector. Why?
Answer:

1. Unorganised sector is largely outside the control of the government.
2. Rules and regulations are often not followed.
3. Jobs are not regular.
4. Jobs are low paid.
5. It is difficult to avail the leaves.
6. No provision for paid leave.
7. Job is not secure.
8. Working conditions are generally poor.
9. No safety measures followed in work places.
10. Health hazards would be there.
11. No insurance
12. No welfare schemes.

Question 3.
Give examples of the criterion for the measurement of human development.
Answer:
The examples of the criterion for the measurement of human development:

1. Per capita income
2. The education levels of people and health status.
3. Standard of life of the people
4. Availability of electricity
5. Transportation
6. Sanitation facilities
7. Expected years of schooling
8. Average years of schooling, etc.
   Ex: Sri Lanka, one of our neighbours is much ahead of India in every respect.

Question 4.
What are the different indicators in which development is measured? Which one do you agree with ?
Answer:

1. Per capita income
2. Literacy rate
3. Average years of schooling 4) Expected years of schooling
4. Life expectancy at birth 6) Health status
5. Employment status 8) Equal distribution
6. I agree with all the above things because those are useful for measuring the complete development.

Question 5.
Give examples for different persons can have different developmental goals.
Answer:

Category of persons	Developmental goals
Landless rural labourers:	More days of work and better wages, quality education for their children, no social discrimination.
Prosperous farmers:	Higher support prices for crops, should be able to settle their children abroad.
Farmers who depend only on rains for growing crops:	Adequate rainfall.
Urban unemployed youth:	High salaried jobs
An Adivasi from mining fields :	To protect their livelihoods.
Persons from fishing community in the coastal area.	Good weather and a good catch of fisher.

Question 6.
What do the people desire other than income?
Answer:
People desire the following other than income.

1. Equal treatment
2. Freedom
3. Security
4. Respect from others.

Question 7.
Prepare a pamphlet on making mahila mandals active in villages.
Answer:
Mahila Mandals are voluntary service organizations that work for the betterment of women in the villages of India. To better their life the village women should have their say in the active involvement of Mahila Mandals’ activities. Active Mahila Mandals can be found In many villages. Suggestions to make Mahila Mandals active in the villages:

• First priority should be given to girl education and to eradicate illiteracy.
• Vocational training and credit facilities to women for self-employment should be provided.
• Mahila Mandals should collectively work for the betterment of women who need nutrition, education and family welfare.
• They should help the women in immunization of children, small savings, provision of bathrooms, women crafts centres and balwadis.
• They should work towards the elimination of discrimination, inequality, intolerance, and violence-both, within and outside the home.
• They should have comparatively high involvement in social life and village politics.

The government should provide basic equipment and stationery, etc. to the Mahila Mandals. It should create awareness among women regarding the Mahila Mandals.

Women empowerment leads to a strong nation.

Copies: 2000

Surya Printers.

Question 8.
What is Development ? Why do different people have different developemntal goals? Explain with two Examples.
Answer:
Meaning of Development:

1. Growth plus change is called development. .
2. All the persons may not have the same notion of development or progress.
3. Each one of them seeks different things.
   Examples:
   i) A girl expects as much freedom and opportunity as her brother and that he also shares in the household work.
   ii) To get more electricity, industrialists, may want more dams. But this may submerge the land and disrupt the lives of people who are displaced as the tribals.

Question 9.
Create a few slogans on promoting girl education.
Answer:

1. Girl with education – helpful to the family.
2. Educate a girl – she educates a family.
3. Encourage girl education – save the nation.
4. An educated girl – serves the nation well.
   (Students can sit together and discuss to prepare a few slogans of their own.)

Question 10.
Observe the following table and prepare a paragraph on it.
Answer:
Progress in Himachal Pradesh
The comparison across two different years is indicative of development that has happened. Clearly, there has been greater development in schooling and spread of education in Himachal Pradesh than India as a whole. Though there is still a lot of difference in the average levels of education among boys and girls, i.e., across genders, there has been some progress towards greater equal¬ity in the recent years.

Question 11.
Why was it necessary for government to run schools in Himachal Pradesh?
Answer:
The rich children can get the education in private sector schools. But the majority of Indian chil¬dren are enrolled in the government schools. Education has also been made free for children from 6 to 14 years of age or up to VIII class under the R.T.E. Act 2009. So, it was necessary for government to run schools in Himachal Pradesh.

Question 12.
‘Human development is the essence of social development’ – Explain.
Answer:

1. Human development focuses on the people.
2. It is concerned with the well-being of the people, their needs, choices and aspirations. All these help in building a right kind of society.
3. It is all about the enlarging or widening the choices for the people. It is the building of human capabilities, such as education, information and knowledge, to have opportunities of livelihood.
4. Human development focuses on the expansion of basic choices.

Question 13.
‘Money cannot buy all the goods and services that one needs to live well.’ Explain.
Answer:

1. Even though per capita income is high in many states, education and health facilities are still lacking.
2. Money or high per capita income cannot buy a pollution-free environment or good health.
3. Money cannot buy peace and democracy.

10th Class Social 2nd Lesson Ideas of Development 4 Marks Important Questions and Answers

Question 1.
Study the following table and answer the questions that given below.
(a) What do you mean by literacy rate?
Answer:
The number of literates per every 100 persons in the population is known as literacy rate.

(b) In which state the net attendance is highest?
Answer:
Himachal Pradesh.

(c) What could be the reason for the highest, Literacy rate in Himachal Pradesh?
Answer:

1. Both the government of Himachal Pradesh and the people of the state were keen on education.
2. The government started schools and made sure that education was largely free, or costs very little for parents.
3. Further, it tried to ensure that these schools had at least the minimum facilities of teach¬ers, classrooms, toilets, drinking water, etc.

(d) In which state the IMR is least?
Answer:
Himachal Pradesh.

Question 2.
Read the following paragraph :
“In many parts of the country, girls’ are still given less priority by parents compared to boys.”
Comment on the gender bias in India.
Answer:

1. Ours is a male-dominated society.
2. Female literacy rate is low.
3. Women who work outside their homes are less in number.
4. Traditionally, in our society, women have less involvement in social life.
5. Because of all these reasons, gender bias is still continuing.
6. This is a hurdle for the development of society.
7. Boys and girls should be treated equally.

Question 3.
“We should be able to integrate environmental concerns with the idea of progress”. Explain.
Answer:

1. We must show concern on environmental issues while achieving development.
2. The environmental source function will deplete while using the sources in a speedy way.
3. When waste output exceeds the limit, it will cause long-term damage to the environment.
4. The big projects may harm bio-diversity.
5. Use of chemical fertilizers and pesticides in modern agriculture leads to a big loss to the environment.
6. The fuel used as a part of industrial development causes a lot of air pollution.
7. Ground water levels are being depleted.
8. Deforestation is being occurred.
9. The rights of low-income countries, future generations also should be viewed.

Question 4.
Plot the below information on a bar graph. Write your observation.

SI. No.	State	Literacy rate (%)
1.	Punjab	77
2.	Himachal Pradesh	84
3.	Bihar	64

Answer:
Observation:
As Himachal Pradesh has high literacy rate, it can be considered as developed state.

Question 5.
Read the given paragraph and comment.
In many parts of the country, girls’ education is still given less priority by the parents as compared to boys’ education. While girls may study for a few years, they may not complete their schooling.
Answer:
According to this paragraph two things are clearly mentioned that there is a gender bias with regard to giving education to boys and girls among the people of the country and the second one is only the Himachali Pradesh Government is concentrating on girl education.
My opinion on these two issues is that the gender bias was there once in the society. As there is a vast awareness in the parents they send their daughters to the schools in many places. Even a rickshaw puller also wants to make his daughter study in a school.
He hopes his daughter becomes a professional. The parents are interested to send their children to English medium schools irrespective of their income and status. It shows their interest. A little bit fear about girls is there among them because of other reasons. They are afraid of the safety of their daughters. Just like in Himachal Pradesh other states are also spending much amount on education and schooling. It is accepted that the Himachal Pradesh state has taken the step earlier. I don’t say that other states are not taking steps to improve the conditions of schools for providing good education for the girls.
It is a sensitive issue and it is to be taken seriously to bring awareness among people to make their daughters admit in schools and the governments should consider the problems of girls in schools. Sufficient toilets and other facilities are to be provided so as to enroll all the girls in schools.

Question 6.
Observe the table and answer the following questions.
Some data regarding India and its neighbours for 2013

Country	Per capita  Income in $	Life Expectancy at birth (Years)	Average years of schooling	Expected years of schooling	Human Development Index (HDI) rank in the world
Sri Lanka	5170	75.1	9.3	12.7	92
India	3285	65.8	4.4	10.7	136
Pakistan	2566	65.7	4.9	7.3	146
Myanmar	1817	65.7	3.9	9.4	149
Bangladesh	1785	69.2	4.8	8.1	146
Nepal	1137	69.1	3.2	8.9	157

1. Which country stands ahead of India in all aspects in HDI ?
   Answer:
   The country Sri Lanka stands ahead of India in all aspects in HDI.
2. Mention the aspects that are considered in making Human Development Index.
   Answer:
   1. Percapita income
   2. Literacy Rate
   3. Average years of schooling
   4. Expected years of schooling
   5. Life expectancy at birth
   6. Health status, etc. are the aspects considered in making Human Development Index.
3. Name the country that has the lowest per capita income.
   Answer:
   The country Nepal has the lowest per capita income.
4. Give two suggestions for the improvement of the rank of India in HDI.
   Answer:
   1. Education should be improved and more skill development centres should be established.
   2. The poor and needy people should be provided cheap and better health facilities.

Question 7.
Observe the given table and analyse the HDI data of India and its neighbours.
Some data regarding India and its neighbours for 2016

Country	Per capita income in $	Life expectancy at birth	Literacy rate	Human Development Index (HDI)
Sri Lanka	10,789	74.9	92.6	70
India	5,663	68.3	74.04	131
Pakistan	5,031	66.2	60.0	148
Myanmar	4,943	65.9	93.1	146
Bangladesh	3,341	71.6	61.5	140
Nepal	2,337	69.6	64.7	144

Answer:
The given table is about Human Development data of India and some of the neighbouring countries pertaining to 2016. In this table per capita income in dollars, life expectancy at birth and literacy rate are considered and HDI Ranking is given. In per capita income Sri Lanka stands high and in the same of life expectancy but in literacy Myanmar is better than Srilanka. Pakistan is very poor in literacy rate and so Bangladesh. These countries do not show interest on literacy. In over all ranking Srilanka stands well, Pakistan’s ranking is least. Countries should concentrate on what (the people need proper medication, medical facilities to the poorer people, wide availabiltiy of
104,108 services are essential in rural areas. In Telangana to some extent these services are provided. Each one teach one programme is to be maintained so that all people will be literated. Schooling should be strengthened. Per capita income should be spent on Health facilities and education. Priorities are to be set first and proper planning for its implementation is essential. So that countries can be developed.

Question 8.
Read the text and interpret it.
The ongoing protest over the Kudankulam Nuclear Power Project in theTirunelveli district of Tamil Nadu is one such conflict. The government of India set up the nuclear power plant in this quiet coastal town of fisher folks. The aim is to generate nuclear power to meet the growing energy needs of the country. The people in the region have protested on the grounds of safety, security and livelihood.
Answer:

1. The Government of India is going on with the Nuclear Power Project of the Kundankulum.
2. The aim of the project is to generate nuclear power to meet the growing energy needs of the people.
3. The fisher folks of this area are protesting against the project on the grounds of safety, security and livelihood.
4. Hence the ideas on development are different for different people.
5. Development for one may not be the development for other.
6. Here the ideas on development of government is conflicting with the interests of the local people.

Question 9.
Read the following text and state your opinion on it.

Human Development Report

When we realise that even though the level of income is important, it is an inadequate measure of the level of development, we begin to think of other criterion. There could be a long list of such criteria but then it would not be so useful. What we need is a small number of the most important things. Health and education indicators, such as the ones we used in comparison of Kerala and Punjab, are among them. Over the past decade or so, health and education indicators have come to be widely used along with income as a measure of development. For instance, Human Development Report published by United Nations Development Programme (UNDP) compares countries based on the educational levels of the people, their health status and per capita Income.

Answer:

1. The income is not the correct criteria to measure the level of development.
2. Most of the time it hides disparities.
3. So we begin to think of another criterion.
4. There could be a long list of criteria.
5. We selected some such as “health and education”.
6. Health and Education indicators were used to compare Punjab and Kerala.
7. Human Development Report was published by UNDP.
8. The countries were compared on the basis of the education levels of the people, health status and per capita income.

Question 10.
Read the following paragraph and write your opinion.
If you get a job in afar off place, you would try to consider many factors, apart from income.
This could be facilities for your family, working atmosphere or opportunity to learn. In another case, a job may give you less pay but may offer regular employment that enhances your sense of security. Another job, however, may offer high pay but no job security and also leave no time for your family. This will reduce your sense of security and freedom.
Answer:

1. According to this paragraph, people give preference to income as well as facilities.
2. They also want to spend time with their families.
3. They need job security and freedom. It is not possible in all the cases.
4. Many workers from India are migrating even to foreign countries for getting work so as to earn something for their livelihoods.
5. Some people are working in cities like Hyderabad by keeping their families at their hometowns.
6. They are losing the opportunity of spending their time with their families. Their living conditions are also not good.
7. Many of them are leading sedentary life. In some cases pay is less but job is secure. In some other cases payment may be high but job security is not there.
8. Whatever it is, I am coming to the conclusion that there are many factors that affect livelihoods.

Question 11.
Read the following paragraph and write your comments.
When we looked at Individual aspirations and goals, we found that people not only think of better income but also have goals such as security, respect of others, equal treatment, freedom, etc. In mind. Similarly, when we think of a nation or a region, we may, besides average income, think of other equally important attributes.
Answer:

1. This paragraph is about the aspirations and goals of the individuals.
2. The people want their income and they want to be treated well.
3. Though the wages are well and good, they don’t want to be ill-treated.
4. Everyone in the society wants to live with dignity which our Constitution promises.
5. Many of the labourers are now looking towards prestige.
6. Some states in our country are getting more per capita income but they are lacking in providing other facilities to the people.
7. Nowadays schooling is very importing to its children.
8. For nations and states the literacy rate, net attendance rate, infant mortality rate are also considered in its development.
9. They have to provide schools, pollution-free atmosphere, unadulterated medicines, to its people for better living.

Question 12.
Read the following paragraph and write your opinion on it.
In many parts of the country, girls’ education is still given less priority by parents compared to
boys’ education. While girls may study for a few classes, they may not complete their schooling.
A welcome trend in Himachal Pradesh is the lower gender bias. Himachali parents have ambitious educational goals for their girls, just as for their boys.
Answer:

1. According to this paragraph two things are clearly mentioned that there is a gender bias with regard to giving education to boys and girls among the people of the country.
2. Only the Himachali Pradesh Government is concentrating on girl education.
3. My opinion on these two,issues is that the gender bias was there once in the society.
4. As there is a vast awareness in the parents they send their daughters to the schools in many
   places.
5. Even a rickshaw puller also wants to make his daughter study In a school.
6. He hopes his daughter becomes a professional.
7. The parents are interested to send their children to English medium schools Irrespective of their income and status.
8. It is a sensitive issue and it is to be taken seriously to bring awareness among people to make their daughters admitted in schools and the governments should consider the problems of girls in schools.
9. Sufficient toilets and other facilities are to be provided so as to enroll all the girls In schools.

Question 13.
Table: Read the following table and answer the following questions.
Some Comparative data of Selected States

state	IMR per 1000 (2006)	Literacy rate (%) {2011)	Net Attendance Rate (2006)
Punjab	42	77	76
Himachal Pradesh	36	84	90
Bihar	62	64	56

1.  What does the table tell us?
   Answer:
   The table tells us about some comparative data of selected states.
2. What are the three states compared here?
   Answer:
   The three states compared are Punjab, Himachal Pradesh and Bihar.
3. What does IMR mean?
   Answer:
   IMR means Infant Mortality Rate.
4. Which state ranks best in literacy rate?
   Answer:
   Himachal Pradesh ranks best in literacy rate with 84%.
5. What is the Net Attendance Rate of Bihar in 2006?
   Answer:
   The Net Attendance Rate of Bihar in 2006 is 56.
6. What is the position of Punjab in 2011 with regard to literacy rate?
   Answer:
   The position of Punjab in 2011 with regard to literacy rate is next to Himachal Pradesh.
7. What is literacy rate?
   Answer:
   Literacy rate is that the percentage of literate people in the 7 and above years age group.
8. Why is the number of children below the age of 6 not considered for counting of Net Atten¬dance Rate?
   Answer:
   The children below the age of 6 do not go to school.
9. Which state ranks first when we consider the above data ?
   Answer:
   Himachal Pradesh ranks first.
10. How do you say Bihar is an underdeveloped state ?
    Answer:
    Bihar has high infant mortality rate i.e., 62. It has less literacy rate and Net attendance rate i.e., 64 and 56 respectively. Hence we can say Bihar is a backward state.

Question 14.
Study the table given and answer the following questions.
Table: Some data regarding India and its neighbours for 2013

Country	Per Capita Income in $	Life expectancy at birth (Years)	Average years of schooling	Expected years of schooling	Human Develop­ment Index (HDI) rank in the world
Sri Lanka	5170	75.1	9.3	12.7	92
India	3285	65.8	4.4	10.7	136
Pakistan	2566	65.7	4.9	7.3	146
Myanmar	1817	65.7	3.9	9.4	149
Bangladesh	1785	69.2	4.8	8.1	146
Nepal	1137	69.1	3.2	8.9	157

1. What is the table about?
   Answer:
   The table is about some data regarding India and its neighboring countries for 2013.
2. What is the life expectancy at birth in India?
   Answer:
   The life expectancy at birth in India is 65.8 years.
3. What components are considered in this table?
   Answer:
   The components considered in the table are per capita income, life expectancy at birth, aver¬age years of schooling, expected years of schooling and HDI.
4. Which country ranks best in HDI?
   Answer:
   Sri Lanka ranks best in HDI with 92nd rank.
5. Which country is lacking in expected years of schooling?
   Answer:
   Pakistan is lacking in expected years of schooling.
6. Per capita income is shown in some symbol. What does it mean?
   Answer:
   The symbol given means dollar.
7. Which country has the lowest average years of schooling?
   Answer:
   Nepal has the lowest average years of schooling.
8. What is the per capita income of India ?
   Answer:
   The per capita income of India is $ 3,285.
9. What is the lowest life expectancy at birth in the table?
   Answer:
   65.7 years is the lowest life expectancy at birth in the table.
10. What is the difference between expected years of schooling and average years of schooling
    for India?
    Answer:
    The difference between expected years of schooling and average years of schooling for India is 6.3 years.

Question 15.
By studying the given map answer the following questions.

1. Name two countries which have low income.
   Answer:
   Zimbabwe and Kenya are the two countries with low income.
2. Which two countries have very high income?
   Answer:
   USA and Canada are the two countries which have very high income.
3. Name two countries with high income.
   Answer:
   Brazil and Russia are the two countries with high income.
4. Which two countries have medium income?
   Answer:
   India and Egypt are the two countries which have medium income.

Question 16.
Prepare a pamphlet on Promoting Girl Education.
Answer:

PROMOTING GIRL EDUCATION

Girls and boys in the society are equal but many of the parents give less importance to girl education compared to boys. This treatment of girls and boys in different ways is called gender bias. Some parents feel that boy is income and girl is expenditure. After marriage also the in-law’s family of the bride normally gives very less importance to her education. This is the wrong notion that the people have. It is to be removed.
The notion is to be changed. Many women have come forward to discharge their duties in political, educational and administrative areas. They are proving that they can do everything. In education also many girls are getting good results and ranks. Their number in civil services and other competitive examinations is rapidly increasing. If a girl is educated, she can manage her family herself well.
She can educate her children.
Many women now are district collectors or police officers and administrative officers and a few banks are being run under the leadership of female authorities. Many departments are under their control. For many years it has been a custom that the women have to work at kitchen but it is disproved, if they were given choice to do something they can do it as we expected.
All the parents should send their daughters to schools to study. They should be given an opportunity to show their intellect. All the parents should understand that their notion is to be
changed and think positively about their daughters’ future.

Question 17.
Write a paragraph after reading the table.
Answer:
Comparison of two countries

Name of the country	Monthly incomes of citizens in 2014 (in Rupees)
Country A	1	II	III	IV	V	Average
	9,500	10500	9,800	10000	10200	10,000
Country B	500	500	500	500	48000	10,000

According to this table in the country ‘A’, all the five persons are earning mostly equal monthly income. In the country ‘B’ the first four persons are earning only five hundred each but the fifth person is earning forty eight thousand rupees per month. If you are the fifth one it is OK but if you are one among the first four it will be worst to live in. If we consider the average, it will be the same as ten thousand per person per month. In these two countries the country A has more equitable distribution of income.
In many countries more income is there with a few persons. Many people in the countries are poor. They don’t have minimum amount of income for their livelihoods. In the above table the average income of the two countries is the same but in B it is not equally distributed. The Gross Domestic Product is to be distributed among the people of the country that means the poor also have to get their share in the country. The gap between the poor and the rich is to be removed and so the society of equality emerged.

Question 18.
Locate the following in the given map of India.

1. Nuclear power plant in Tamil Nadu.
   Answer:
   Kudankulam
2. Schooling Revolution took place in the state.
   Answer:
   Himachal Pradesh
3. Draw the Indian standard time.
   Answer:
   82 1/2° E longitude.
4. Sahyadri Range.
5. Islands in Bay of Bengal.
   Answer:
   Andoman & Nicobar
6. Locate any one of Hill station.
   Answer:
   Nainital
7. River which is flowing through a rift valley.
   Answer:
   Narmada
8. The Hill Station located near Nilgiris.
   Answer:
   Ooty
9. The largest river in South India.
   Answer:
   Godavari
10. The largest river in India.
    Answer:
    Ganga

AP State Board Syllabus AP SSC 10th Class Biology Solutions Chapter 6 Reproduction – The Generating System Textbook Questions and Answers.

AP State Syllabus SSC 10th Class Biology Solutions 6th Lesson Reproduction – The Generating System

10th Class Biology 6th Lesson Reproduction – The Generating System Textbook Questions and Answers

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Question 1.
Why do fish and frog produce a huge number of eggs each year?
Answer:

1. External fertilisation occurs in fish and frog.
2. The female lays a vast number of eggs in water and male releases some millions of sperms on to them in water.
3. Eggs may be carried to a long-distance by water currents or they may be eaten by predators.
4. So fertilisation is a chance factor and controlled by nature.
5. Fertilisation occurs externally hence it is inevitable to give rise to vast number of eggs by fish and frog.

Question 2.
Give examples and explain what is meant by external fertilisation?
Answer:

1. Fusion of the male and female gametes is called fertilisation.
2. The fertilized egg (ovum) is called zygote.
3. If the fertilisation occurs outside the body of the female organism then it is called external fertilisation.
4. External fertilisation is seen in fish, frog and earthworm, etc.

Question 3.
Write the differences between
a) Grafting – Layering b) Stamen – Carpel.
Answer:
a) Differences between Grafting and Layering.

Grafting	Layering
1. Grafting is a technique of inserting a part of one plant into another plant in such a way that the two will unite and continue their growth.	1. Stems that form roots while still attached to the parent plants are called layers. Propagating the plants in this method is known as layering.
2. Two plants of the same species are required for grafting.	2. Only one plant is required for layering.
3. Grafting helps to pressure and perpetuate varieties that cannot reproduce by vegetative method.	3. In layering we can propagate the plant varieties which are required by us.
4. Grafting is used to obtain a plant with desirable characters.	4. In layering the plant already has desirable characters is propagated.
5. The two plants stock and scion and joined together in such a way that two stems join and grow as a single plant.	5. The common practice in layering is to injure the portion to be layered by notching, cutting, girdling.
6. Ex: Mango, apple, guava, etc.	6. Ex: Jasmine, rose, grapevine, etc.

b) Differences between Stamen and Carpel.

Stamen	Carpel
1. Male reproductive organ of the flowering plant.	1. Female reproductive organ of the flowering plant.
2. It has two parts – anther and filament.	2. It has three parts – style, stigma and ovary.
3. Stamen produces pollen grains.	3. Carpel produces ovule.
4. Pollen grain contains the male gamete.	4. Ovule contains the female gamete ovum or egg.

Question 4.
Describe the mode of fertilization in plants with a diagram.
Answer:

1. Fertilisation is the process of fusion of male and female gametes.
2. For the fusion of male and female gametes pollen grains have to reach the surface of the stigma. This is called pollination.
3. Pollen grains received by the stigma germinate and give rise to pollen tubes. Only one pollen tube finally reaches the embryo-sac.
4. This tube will have two male nuclei, which migrate to the tip of the pollen tube at the time of fertilization.
   
5. Usually the pollen tube enters the ovule through micropyle and discharges the two male gametes into its embryo-sac.
6. One male nucleus (n) or (gamete) approaches the egg and fuses with it to form a diploid (2n) zygote. This is first fertilisation.
7. The other male nucleus (n) or (gamete) reaches the secondary nucleus (2n) and fuses with it to form the endosperm nucleus which will be triploid. This is second fertilization in the embryo-sac.
8. Thus double fertilisation occurs in embryo-sac which is unique in flowering plants.

Question 5.
What are the different modes of asexual reproduction? Cite them with examples.
Answer:
Asexual reproduction takes place by six different methods. They are:

1. Fission
2. Budding
3. Spore formation
4. Regeneration
5. Fragmentation and
6. Vegetative propagation.

1. Fission: Single-celled organisms split into two equal offsprings or more offsprings. Ex: Paramoecium, bacteria.

2. Budding: A growth on the body as a bud grows to form identical copy of parent. Ex: Yeast.

3. Spore formation : Spores are produced in the sporangium.
Ex : Rhizopus, mucor, bacteria, ferns and mosses.

4. Regeneration :
a) Ability of organisms to give rise to new individual organisms from their body parts.
b) That is if the individual is some how cut or broken up into many pieces, many of these pieces grow into separate individuals.
Ex: Hydra and Planaria.

5. Fragmentation:
a) In multicellular organisms with relatively simple body organisation breaks up into smaller pieces upon maturation.
b) These pieces of fragments grow into new individuals.
Ex: Flatworms, Spirogyra, moulds, lichens.

6. Parthenogenesis: In the process generally the female gametes or ova develop into zygote without fertilization.
Ex : Bees, ants and wasps.

7. Vegetative propagation: When a vegetative part like stem, root and leaf can produce a new organism it is called vegetative propagation. It is of two types.
a) Natural propagation:
Bryophyllum Dahlia, Carrot, Radish
b) Artificial propagation:
i) Layering: Eg: Nerium, Guava, Orange, Rose
ii) Cutting: Eg: Rose, Hibiscus, Sugarcane
iii) Grafting: Eg: Sapota, Guava, Mango, etc.

Question 6.
In what ways does sexual reproduction differ from asexual one? State at least three reasons.
(OR)
What are the differences between sexual and asexual reproduction?
Answer:

Sexual reproduction	Asexual reproduction
1. Two parents are required.	1. One parent is needed.
2. Gametes are formed.	2. Gametes are not formed.
3. Fertilization takes place.	3. Fertilization does not take place.
4. Zygote is formed.	4. Zygote is not formed.
5. New characters are formed.	5. New characters are not formed but only through mutation.
6. Meiosis takes place.	6. Meiosis does not take place.
7. Found in higher animals.	7. Found in lower animals.
8. Support to evolution process.	8. Supports evolution but not frequently.
9. Takes several months to complete.	9. Takes very short period to complete.

Apart from the above differences Sexual and Asexual reproduction differs in the following ways:

1. The unit of reproduction in sexual reproduction is gamete whereas in asexual repro-duction it may be whole parent body or bud or a fragment or a single somatic cell.
2. Sexual reproduction need more time to complete and it is less time in asexual reproduction.

Question 7.
How are sperm cells adapted for their function?
Answer:

1. Sperm cell is adapted to its function by carrying genetic information to an egg.
2. Its body consists of four parts :
   1. Head
   2. Neck
   3. Middle piece and
   4. Tail.
3. Sperm has a streamlined body that allows it to move quickly.
4. Nucleus is present in the head.
5. Special structure on the head called acrosome helps in penetrating the ovum during fertilisation.
6. The head of sperms also contain enzymes to breakdown and digest the zone on the egg through which it penetrates and fertilise it.
7. Large number of mitochondria are present in the mid-region, so it is able to produce a lot of energy in order to operate tail.
8. Its tail allows it to swim towards the egg for fertilisation.

Question 8.
The menstrual cycle prepares the uterus for a fertilised egg. How long is an average menstrual cycle from start to finish?
Answer:

1. The cycle of changes that occur in the female reproductive system is called menstrual cycle.
2. The average menstrual cycle from start to finish is 28 days long.

Question 9.
When the foetus is growing inside the uterus it needs nutrients? What provides these nutrients?
Answer:

1. When the foetus is growing inside the uterus it needs nutrients for its growth and development.
2. These nutrients are provided by the mother’s blood through a special structure called placenta.
3. Placenta is a tissue formed by the cells from the embryo and the mother.
4. It is formed around 12 weeks of pregnancy and becomes an important structure for nourishment of the embryo.
5. The foetus is connected to placenta in mother’s body through umbilical cord.

Question 10.
Which type of substances are absorbed by foetus from the mother?
Answer:

1. The digested food from the mother travel through the mother’s blood stream and exchange to the blood stream of the foetus through the placenta.
2. In addition to ingested food the mother’s body continuously breakes down muscles, fat and bones.
3. Releasing proteins, fat and calcium to the mother’s blood that can be absorbed through the placenta to provide nutrients to the foetus.
4. Some hormones also transfer to baby.

Question 11.
What is the job of Amniotic sac?
Answer:

1. The amniotic sac is a bag of fluid inside a women’s womb (uterus) where the embryo and foetus develops and grows.
2. The cavity within the amnion becomes filled with fluid called amniotic fluid.
3. The embryo or unborn baby floats and moves in the amniotic fluid.
4. Amniotic sac and amniotic fluid give protection against minor mechanical injury.
5. This fluid also provides a stable temperature and assists in maintaining a consistent body temperature for the unborn child.

Question 12.
What are the advantages of sexual reproduction?
(OR)
What are uses of sexual reproduction?
Answer:
Advantages of sexual reproduction:

1. Sexual reproduction promotes diversity of characters in the offsprings by providing genetic variation.
2. It plays an important role in the origin of new species have different characters.
3. This genetic variation leads to the continuous evolution of various species to form better and still better organisms.
4. Sexual reproduction influences in diversity of characters in offsprings.
5. It helps to maintain the continuty of organisms.
6. It leads to new generation to tolerate adverse or diseased conditions.
7. It helps the spreading of population to new areas.

Question 13.
How does reproduction help in providing stability to population of species?
Answer:

1. The reproduction is directly linked to the stability of the population of species because it helps in replacing the lost or aging population with the new population and thus ensures the survival of the species.
2. The process of reproduction ensure continuity of life on earth.
3. In the absence of reproduction one particular species will disappear with time.
4. Reproduction induces variations in the population which help the population to tide over adverse environmental conditions and adapt to changing environment.
5. Reproduction also helps to generate copies of individuals which are suited to a particular environment.

Question 14.
Write the differences between mitosis and meiosis.
Answer:

Mitosis	Meiosis
1. It occurs in somatic cells.	1. It occurs in germ cells.
2. Nucleus divides only once.	2. Nucleus divides twice.
3. Two daughter cells are formed.	3. Four daughter cells are formed.
4. Daughter cells are diploid.	4. Daughter cells are haploid.
5. It occurs more frequently.	5. It occurs less frequently.
6. Daughter cells form somatic organs.	6. Daughter cells form gametes.
7. There is only one prophase, one metaphase one anaphase and one telophase.	7. There are two of each phase and five sub-phases in prophase -1.
8. Number of chromosomes are not changed in the daughter cells.	8. Number of chromosomes are reduced to half.
9. Chromosome number doubles at the beginning of each cell division.	9. Chromosome number is not doubled. It doubles after the end of first meiotic division.
10. No crossing over in chromosomes.	10. Crossing over occurs chromosomes.
11. Equation division.	11. Reduction division.

Question 15.
What happens to the wall of the uterus during menstruation? (OR)
What changes occur in the wall of the uterus during menstruation?
Answer:

1. During the early stage of menstruation the cells in the wall of uterus increase in number by repeated mitotic divisions.
2. The inner lining of uterus becomes thick and soft with lot of blood capillaries in it.
3. These changes in the uterus are necessary because in case the ovum released by the ovary gets fertilised by the sperm, then the uterus has to keep this fertilised ovum for further development and supply it with food and oxygen etc.
4. If fertilisation does not occur the additional growth of the uterus is detached and expelled along with some amount of blood.

Question 16.
“All unicellular organisms undergo only mitotic cell division during favourable conditions” – Do you support this statement? Why?
Answer:

1. Unicellular organisms undergo mitotic cell division not only during favourable conditions but also in unfavourable conditions.
   So I don’t support the given statement.
2. When the organism finds favourable conditions it deserves to perform division called Fission. Ex: Amoeba.
3. Sometimes scarcity of food or to save it life, some organisms undergo mitotic cell division.
4. Organisms like paramoecium undergo a type of sexual reproduction called conjugation during unfavourable conditions.

Question 17.
What would be the consequences if there is no meiosis in organisms that reproduce sexually?
(OR)
What happens if Meiosis does not take place in reproductive cells?
Answer:

1. If meiosis did not occur, a fusion of gametes would result in a doubling of the chromosomes for each successive reproduced generation.
2. For example, in case of man egg cells and sperm cells like other cells must contain 46 chromosomes.
   
3. This results in the formation of abnormalities in each generation.
4. If meiosis did not occur, there is no genetic variation in the offsprings produced by random fusion of the gametes.
5. New characters will not appear in the offsprings.
6. The process of evolution will be stopped.

Question 18.
Vicky’s father wants to grow a single plant having two desirable characters colourful flowers and big fruits. What method will you suggest to him and why?
Answer:

1. I will suggest the method of grafting to him.
2. Grafting enables us to combine the most desirable characteristics of two plants into a single plant with colourful flowers and big fruits.
3. By grafting method, a very young scion can be made to flower and produce fruits fast when it is grafted to the stock.
4. Vicky’s father can grow one of the two plants as stock and second plant can be graft to some of its branches as scions.
5. Then he can get the plant with both the desirable characters.

Question 19.
Uproot an onion plant and take a thin section of its root tip. Stain it and observe under the microscope. Draw as you see and identify the stages of the cell division.
Answer:

Question 20.
Visit a nearby village and collect information on how farmers grow sugarcane, flowering plants like chrysanthemum, primerose and vegetables like stem tubers, plump gourd (dondakaya), etc. Make a report and present in class.
Answer:
Report on growing methods of various plants :

Plant name	Growing method
Sugarcane	Stem bits with nodes called seed pieces or sets can be planted horizontally in the farrows.
Chrysanthemum	It propagates often by means of suckers (the basal shoot). But some farmers grow these using seeds or the transplanted nursery plants.
Primerose	These are generally grown using cuttings. Its root ball should be cut vertically making sure that each half has at least 2 plant stems.
Potatoes	These are the stem tubers. The nodes on the potato are called eyes which sprout out and grow into a new plant.
Plumpgourd	These have tubers just below the ground which on cutting and planting in soil can give rise to new plants.

Question 21.
Collect the information from school library or using internet what vegetative methods are followed in your district as well as in your state to propagate various plants of economic importance. Represent it with a graph.
Answer:
Vegetative methods followed in our district as well as in our state to propagate various plants of economic importance.
I) Natural vegetative propagation: In this method of vegetative propagation, a part of the plant which may be stem, root-leaf or flower gets detached from the body of the mother plant.

1. Vegetative propagation: Roots of radish, carrot, dahlia develop adventious buds which grow into leafy shoots.
2. Vegetative propagation by stems: Stolons – Vallisneria, offsets – Eichhornia, Rhizome – Banana, Ginger Bulbs – Alliumcepa (Onion); Corn – Colacasia; Tuber – Potato.
3. Vegetative propagation by leaves: Bryophyllum.
4. Vegetative propagation by modified flowers (Bulbils): Agave.

II) Artificial vegetative propagation: Certain flowering plants have the capacity to develop a part of their somatic body into a new independent plant. In artificial vegetative propagation such plants are identified and special techniques are applied to obtain new independent plant.

1. Cutting (Stems): Sugarcane, Roses, Hibiscus, Citrus plants.
2. Cutting (Root): Lemon, Tamarind.
3. Layering: Jasmine, Strawberry, Gooseberry.
4. Grafting: Rubber, Apple, Pear, Citrus, Mango, Guava.
5. Propagation by tissue culture technique: Lily, Rose, Magnolia, Fern, Banana for micropropagation, a small amount of tissue from a suitable part of the parent plant is excised and grown on a nutrient medium under aseptic conditions.

Question 22.
Make a flow chart to show the cell cycle and explain cell division describing different stages of mitosis.
Answer:

Different stages of mitotic cell division:

Stage	Description
1) Prophase	Chromatin condenses to form chromosomes. Chrormisomes split length ways to form chromatids, connected by centromeres. Nuclear membrane breaks down.
2) Metaphase	Chromosomes move to spindle equator, centromeres attached to spindle fibres. Centromeres split, separating the chromatids.
3) Anaphase	Spindle fibres attached to centromeres contract, pulling chromatids towards poles.
4) Telophase	Chromatids elongate, become invisible. Nuclear membranes form round daughter nuclei. Nucleus divides into two and division of cytoplasm starts.
5) Cytokinesis	Cytoplasm divides to form two daughter cells.

Question 23.
Draw neat labelled diagrams of male and female reproductive systems of plant.
Answer:

Question 24.
Observe the following part of flowering plant and prepare a note.
Answer:
The given diagram is the structure of ovule which is present in the ovary (carpel) of plant.

1. An ovule is an egg shaped structure attached by a stalk (Funicle) to the inner side of the ovary.
2. Depending upon the species of plant involved, an ovary may have one, two, several or even hundreds of ovules.
   
3. At the centre of each ovule is a microscopic embryo sac filled with food and water.
4. The embryo-sac is composed of gametophyte cells.
5. The majority of flowering plants have an embryo sac consisting of seven cells and eight nuclei.
6. They are one egg (female gamete), two synergids, one central cell (secondary nucleus) and three antipodals.
7. Central cell contains two nuclei, they are called polar nuclei.

Question 25.
Prepare a flow chart to explain the process of sexual reproduction in plants
Answer:

Question 26.
Draw a neat labelled diagram to explain plant fertilisation. Write few points on Pollen grain.
Answer:

Pollen grains:

1. Pollen grains develop in anther.
2. Anther consists of spore-forming tissue. Some of the cells in the spore-forming tissue develop as pollen mother cells.
3. Each pollen mother cell undergoes meiosis to form four daughter cells which develop into pollen grains
4. Pollen grains are haploid (‘n’) and are otherwise known as microspores or male gametes.
5. They contain only one set of chromosomes (‘n’).
6. The study of pollen grain is called palynology.
7. During pollination pollen grains are dispersed by wind and insects.
8. Pollen grains are formed in large numbers. They are light in weight and are easily carried by wind currents.

Question 27.
How will you appreciate cell division that helps in perpetuation of life?
Answer:

1. Perpetuation means continuation of life.
2. The perpetuation of life is based on the cell division.
3. Both mitotic and meiotic divisions are very essential for perpetuation of life.
4. In unicellular organisms, the mitotic cell divisions form the entire organisms.
5. Mitotic division is essential for all types of asexual reproductions.
6. In sexually reproducing organisms meiotic cell division helps in formation of gametes with haploid number of chromosomes which fuses to form diploid zygote during fertilization.
7. Zygote further divides by mitosis again and grows into an embryo and then to offspring.
8. Thus both mitotic and meiotic cell divisions play a key role in perpetuation of life. Without cell division, there is no perpetuation of life.

Question 28.
What precautions will you take to keep away from various sexually transmitted?
Answer:
Precautions to be taken to keep away from various sexually transmitted diseases:

1. Avoid sex with any one who has genital sores, a rash, discharge or other symptoms.
2. The only time unprotected sex is a safe if the partners have sex only with each other.
3. I use latex condoms every time 1 participate in sex. I use it for the entire sex act.
4. I avoid sharing towels or under clothing.
5. I wash genital organ before and after intercourse.
6. I will get a vaccination for hepatitis B. This is a series of three shots.
7. I will get tested for HIV for every six months.
8. I will not drunk or take drugs. Under these conditions, I may fail to have safe sex.
9. I consider that not having sex is the only way, sure way to prevent sexually transmitted diseases.
10. Sexual act is supposed to be an act between husband and wife. Hence I will not participate in sex before marriage.
11. When I grow up and get married, I will be upright and faithful to the life partner and will not behave immorally.
12. Hence as a student I will concentrate on studies and create activities to achieve success in life.

Question 29.
Conduct a seminar on child marriages and foeticide.
Answer:
child marriages can also be defined as “any marriage carried out under the age of 18 years and involves the girl who is physically, psychologically, mentally and physiologically immature”.

Causes of Child marriages :

1. Poverty in the families due to unemployment.
2. Illiteracy among people.
3. Ignorance of consequences of child marriages.
4. Strong superstitions among people about child marriages.
5. Religious and traditions are also responsible for occurance of child marriages.

Steps to prevent Child marriages:

1. By creating awareness among the people about the ill effects of child marriages.
2. By educating the people especially in rural areas of backward districts.
3. By providing employment opportunities to all the people.
4. Performing live plays, skits and stage shows to create enlightenment among the rural illiterate women about the pathetic future of kids who are forced to get married.

Foeticide:

1. Foeticide is the illegal practice of killing a foetus. Female foeticide is prevalent in our country as a major social evil.
2. Some kinds of complications in pregnancy can also demand surgical termination of pregnancy after 8 weeks of conception.
3. This is where the abortion is legal and doctors may have to suggest for discontinuous of pregnancy for the sake of health of the mother. However the technique of surgical termination is misused by some people by getting rid of the unborn child.
4. Abortion of foetus is an act of murder. God is the author of life and nobody should have right to take it.

Choose the correct answer.

1. The part of the female reproductive system produces the eggs [ ]
A) Ovary
B) Epididymis
C) Cervix
D) Fallopian tube
Answer: A

2. The term that we use to describe a sperm cell fusing with an egg cell [ ]
A) Fragmentation
B) Fermentation
C) Fertilisation
D) Fusion
Answer: C

3. Which part of the male reproductive system produces (human) the sperm cells ? [ ]
A) Vas deference
B) Epididymis
C) Seminiferous tubules
D) Scrotum
Answer: C

4. How does the sperm break through the egg cell membrane? Choose the option you think is right.   [ ]
A) Tears a hole in the membrane
B) Dissolves the membrane with chemicals
C) Bites through the membrane with teeth
D) Squeezes through gaps in the membrane
Answer: B

5. Why are egg cells larger than sperm cells? Choose the option you think is right. [ ]
A) Egg cells have more cells in them
B) Have food store to help growth after fertilisation
C) Have thicker cell membranes
D) Have larger nuclei
Answer: B

6. Which of these things will affect the way a foetus grows? Choose the option you think is right. [ ]
A) Chemicals in cigarette smoke
B) Alcohol
C) Drugs
D) All of the above
Answer: D

7. Which of the following is the correct sequence of steps in the human life cycle? Choose the right option. [ ]
A) Babyhood, childhood, adolescence, adulthood
B) Childhood, babyhood, adulthood, adolescence
C) Adolescence, babyhood, adulthood, childhood
D) None of the above
Answer: A

10th Class Biology 6th Lesson Reproduction – The Generating System InText Questions and Answers

10th Class Biology Textbook Page No. 117

Question 1.
How do you think bacteria were dividing to form curd?
Answer:
Curdling indicates that the increase in number of bacteria by fission.

10th Class Biology Textbook Page No. 118

Question 2.
How do you think this process (parthenogenesis) happens?
Answer:
This process occurs by the development of female gamete or ovum directly develops into zygote without fertilisation.

Question 3.
What about animals?
Answer:

1. Normally the fertilized ovum (zygote) develops into a young one. But the unfertilized ovum also develops into a young one generally the male.
2. The process of development of young ones from unfertilized ovum is called parthenogenesis.
3. In this process sperms develop by mitotic division whereas ova develop by meiotic division.
4. This strange kind of reproduction occurs in animals like bees and wasps.

Question 4.
Is regeneration can also be known as a type of fragmentation? Do you agree? Why? Why not?
Answer:

1. Yes. I agree that regeneration could be also called as a type of fragmentation. Because in both cases pieces or parts from the body of the organism can develop into a new individual.
2. Fragmentation and regeneration occur in multicellular animals.
3. Fragmentation occurs in organisms with relatively simple body organisation.
4. Whereas regeneration occurs in organisms with fully differentiated body organisation.

Question 5.
Which type of fission would produce larger colonies in less period of time. Why?
Answer:
Multiple fission would produce larger colonies in less period of time because more number of daughter cells are formed by multiple fission.

Question 6.
Which mode of asexual reproduction provides maximum scope of choice of desirable characters?
Answer:
Parthenogenesis provides maximum scope of choice of desirable characters.

10th Class Biology Textbook Page No. 120

Question 7.
What are the characters that would you like to select?
Answer:
The characters that I would like to select are plant with large number of fruits which are big in size and taste sweet with less or no seeds.

Question 8.
What mode of propagation would help you to produce the plants with selected characters?
Answer:
Mode of propagation that would help me to produce the plants with selected characters is grafting.

Question 9.
Whether they reproduce by budding or fission or fragmentation, organisms are copies of their parents. Is it true? Why ?
Answer:

1. Yes, it is true that organisms reproduced by budding or fission or fragmentation are copies of their parents.
2. Because budding or fission or fragments are not the methods of sexual reproduction.
3. No gametes were formed or fused in these methods.
4. Exchange of chromosomes or crossing over do not take place. Hence the offsprings produced are similar to their parents.

10th Class Biology Textbook Page No. 122

Question 10.
Do you find any similarities between rhizopus and fern spores and sporangia?
Answer:

1. Both rhizopus and fern reproduce asexually through spores.
2. In both the spores are microscopic, unicellular bodies produced in the sporangia.

Question 11.
What about mushrooms, how do they grow? Discuss in your class.
Answer:
Fungi grow from the fragmentation of hypae. They also form buds which are bulged from out side of cells which detaches after division of the nucleus. A special reproduc¬tive sac called sporangium produces asexual spores which are released outside. Fun¬gal sexual reproduction includes plasmogamy, Karyogamy and gametangia.

10th Class Biology Textbook Page No. 123

Question 12.
Think why testis are located outside the abdominal cavity?
Answer:
The testis are located outside the abdominal cavity because the temperature required for proper functioning of spermatogenesis is generally 2 to 3 degrees less than the body temperature,

10th Class Biology Textbook Page No. 127

Question 13.
What function do you think is served by petals and sepals?
Answer:

1. Calyx consists of sepals give protection to the flower particularly in bud condition.
2. Corolla consists of bright coloured petals and are useful in attracting insects for pollination.

Question 14.
Draw the diagram of the flower that you collect and label the parts shown and write their functions.
Answer:
Functions of flower parts:

1. Calyx: Consists of sepals – protects flower in bud conditions.
2. Corolla: Consists of coloured petals – helps in pollination.
3. Androecium: Consists of stamens – produce male gametes pollen grains,
4. Gynoecium: Female reproductive part – produce ovules inside the ovary. Stigma receives pollen grain.

10th Class Biology Textbook Page No. 128

Question 15.
How does the male reproductive cell fertilise the female reproductive cell in flowers of such plants (pea plants)?
Answer:

1. In self pollinated plants anthers are usually present above the stigma.
2. Pollen from the anthers drop on the stigma.
3. A process that takes place as the flowers close for the night,
4. And sometimes occurs before they are completely developed and ready to open.
5. At the time of pollination slightest movement of the flower’s petals stimulate the stamen to dislodge its pollen and transfer it to the near by stigma in pea plant.
6. Pollination usually occurs before the flower is fully open, .

10th Class Biology Textbook Page No. 129

Question 16.
How many nuclei are present in the pollen grain?
Answer:
Pollen grain has two nuclei. One is called a tube cell and the another is generative cell.

10th Class Biology Textbook Page No. 131

Question 17.
Which floral part may be seen in a fruit?
Answer:
Sometimes calyx may remain with fruit.

Question 18.
How cotyledons are useful for the plant?
Answer:

1. The cotyledons digest and absorb the endosperm.
2. They make the stored food available for the growth of the epicotyl and hypocotyl.
3. The cotyledons of some flowering plants, digest, absorb, and store the foods from the endosperm as the ovule is maturing into a seed. Eg: beans
4. As a consequence, the cotyledons become greatly enlarged because of stored food and the endosperm disappears more or less completely.

10th Class Biology Textbook Page No. 137

Question 19.
What differences do you find in mitosis and meiosis? Write in a tabular form.
Answer:

Mitosis	Meiosis
1. It occurs in somatic cells.	1. It occurs in germ cells.
2. Nucleus divides only once.	2. Nucleus divides twice.
3. Two daughter cells are formed.	3. Four daughter cells are formed.
4. Daughter cells are diploid.	4. Daughter cells are haploid.
5. It occurs more frequently.	5. It occurs less frequently.
6. Daughter cells form somatic organs.	6. Daughter cells form gametes.
7. There is only one prophase, one metaphase one anaphase and one telophase.	7. There are two of each phase and five sub-phases in prophase -1.
8. Number of chromosomes are not changed in the daughter cells.	8. Number of chromosomes are reduced to half.
9. Chromosome number doubles at the beginning of each cell division.	9. Chromosome number is not doubled. It doubles after the end of first meiotic division.
10. No crossing over in chromosomes.	10. Crossing over occurs chromosomes.
11. Equation division.	11. Reduction division.

Question 20.
What would happen if the gametes do not have half the chromosome number as the skin parent?
Answer:

1. Daughter cells formed in meiosis are gametes.
2. These gametes have half of the chromosomes in number as the parent,
3. If the gametes do not have half of the chromosomes in number as the parent, when they fuse, they form zygote with double the number of chromosomes when compared to parent cell.
4. If it continues, cells in the offspring will have thousands of chromosomes within few generations.
5. If the chromosome number increases in a species it leads to the formation of abnormalities.

Question 21.
How would it affect the progeny formed by sexual reproduction?
Answer:
If the progeny have thousands of chromosomes in them, it results in formation of abnormalities in each generation.

Question 22.
Why did the government of India fixed the legal marriage age of boys (21 years) and girls (18 years)?
Answer:

1. Government of India fixed legal marriage age of boys as 21 years, and girls as 18 years.
2. This is because teenage mothers are not prepared mentally or physically for motherhood.
3. Early marriage and motherhood cause health problems for the mother and child.
4. It may also cause mental agony, as teenage mother is not ready for responsibilities of motherhood.

Question 23.
Do you feel that it is a social responsibility to control birth after having one or two children?
Answer:

1. Yes, it is a social responsibility of every individual to control birth after having one or two children.
2. If we don’t control birth after having one or two children, population will grow rapidly.
3. If the population increases we will not be able to provide all the facilities such as education, medicine, employment etc., to all the people.
4. It shows impact on the economic conditions of the family and the society.
5. The quality of life will decrease.

Question 24.
What do you understand by the term ‘Healthy Society’?
Answer:

1. If all the people in a society are in the state of complete physical, mental and social well being, then the society is said to be healthy society.
2. To be in a healthy society, every one in the society should take care of their own personal hygiene and cleanliness of the surroundings.
3. Avoiding child marriages, unprotected sex and creating awareness among the people regarding adverse effects of these are very essential to form a healthy society.

Question 25.
Will you encourage child marriage? Why?
Answer:

1. No. I will never encourage child marriage.
2. This is because, the sexual act always has potential to lead to pregnancy.
3. In case of child marriage, the age of girls is less than 18 years and so they are not prepared mentally or physically for motherhood.
4. If they got pregnancy the health of them and their child will be affected.

Question 26.
How does HIV is transmitted?
Answer:
Hiv is transmitted by unsafe sexual contacts, using infected devices,infected blood
transfusion, from an infected mother to child, etc.

10th Class Biology Textbook Page No. 138

Question 27.
Social discrimination against AIDS patients is also a social evil. Can you support this? Why?
Answer:

1. Yes, I will support this statement.
2. The persons suffering from HIV/AIDS are shown lot of social discrimination in the society.
3. This happens even with their own family members.
4. This is due to lack of awarness among public about spreading of disease, illiteracy misconception about AIDS.
5. If everyone knows how it will not spread they will treat HIV + ves with love and effection.
6. HIV +ves are patients. It will spread through sexual contact, blood transfusion, mother to child and not with other modes.
7. Hence they can live with us without any discrimination they need our love and family support.
8. If anybody shows discrimination, it is definitely a social evil.

10th Class Biology Textbook Page No. 140

Question 28.
Do you think you have moral right to kill a foetus?
Answer:
No, I don’t think that we have moral right to kill a foetus. It is our social responsibility to protect the foetus.

Question 29.
Why doctors are prohibited to do sex determination through ultrasound scanping for pregnant women?
Answer:
Knowing the sex of foetus inside mother’s womb is a severe crime as per the acfmade by government. Ultrasound tests are mend to know the growing condition of the foetus and also to see whether it is suffering with severe ailments. By knowing the sex of the foetus, if it is female, people are ready for aborting it. This leads to reduction in male female ratio in the country. That’s why doctors are prohibited to do sex determination through ultrasound scanning for pregnant women.

10th Class Biology 5th Lesson Reproduction – The Generating System Activities

Activity – 1

Formation of bacterial colony in milk.
Answer:

1. Take a tea spoon full of curd and mix it thoroughly with around tea spoon full of (half of the glass) luke warm milk in a bowl.
2. Take another tea spoon full of curd and mix it with 30 tea spoon full of cold milk in another bowl,
3. Cover both the bowls and note the initial time.
4. Keep observing every hour to see whether curd has formed.
5. Curdling indicates that the increase in number of bacteria.
6. Note the time taken for formation of curd in both the bowls.

• Does it take the same time to form curd in both the bowls?
  Answer: No. Formation of curd in the bowl containing luke warm milk takes nearly 5 – 6 hours. In the second bowl in which cold milk is present no curdling took place.
• What does the time taken to form nearly 30 times the size of the bacterial colony indicate?
  Answer: Time taken to form nearly 30 times the size of the bacterial colony indicates how fast bacteria are growing.

Activity – 2

Examine Rhizopus or common mould under Microscope.
(OR)
Write the materials required and the procedure followed by you to observe Rhizopus in the lab.
(OR)
Write the procedure which you follow to observe bread-mould Sporangium m your laboratory. What precautions do you take during the activity?
(OR)
Suneetha wanted to observe Rhizopus on the piece of bread,
(i) Suggest the apparatus needed. (ii) Write the procedure to be followed.
Answer:
Aim: To grow and examine rhizopus or common mould.
Materials required: Bread, plastic bag, plain glass slide, cover slip, water, eye dropper, disposable gloves, compound microscope.
Procedure to grow mould:

1. Take a soft bread and leave it in the open for about an hour so it is exposed to contaminants in the air.
2. Place the bread in a plastic bag, sprinkle water over it, so it is damp and seal the bag living some air inside.
3. Check on the piece of bread every few days and add more water if it is becoming dried out.
4. We can find whitish thread like growth with masses of black, gray and green fine dotted structures, the black dotted structure is that of bread mould.
5. A good sample of mould may take up to two weeks to form.
6. Using this mould make a slide and observe under the microscope.

Procedure to make a slide:

1. Place a drop of water in the centre of the slide, using an eye dropper if you have one, or the tip of a clean finger.
2. Using a tooth pick, scrape some of the mould off, and place it on the drop of water.
3. Take the coverslip and set it at an angle to the slide so that one edge of it touches the water drop.
4. Then carefully lower it over the drop, so that the coverslip covers the specimen without trapping air bubbles underneath.
5. Use the corner of a tissue paper or blotting paper to blot up any excess water at the edges of the coverslip.
6. View the slide with a compound microscope, starting with a low objective.

Observations:

1. The common bread mould plant consists of fine thread like projections called hyphae and thin stems having knob like structures called sporangia.
2. Each sporangium contains hundreds of minute spores.

Precautions:

1. This should not be done by those with allergies to mould or with severe asthma.
2. Avoid opening the plastic bag as much as you can.
3. If you touch the bread, be sure to thoroughly wash your hands afterwards.

Activity – 3

Observation of pollen grain.

1. Take a slide and put a few drops of water on it.
2. Take any flower like hibiscus, tridax, marigold, etc. Tap the anther over the drop of water.
3. We will see small dot like structures in water. These are pollen grains.
4. Take permanent slide of pollen grain from your lab.
5. Also see a permanent slide of pollen grain from our lab.
6. Observe under a microscope. We will make a drawing of what we observe and compare with the given diagram.

Observation: Pollen grain germinates only on stigma. Pollen grain consists of two to three cel Is surrounded by a protective wall in Angiosperms. In gymnosperms the pollen grain consists of several living cells.

Activity – 4

Seed germination.
Answer:

1. Soak a few groundnut or bengal gram (chana) seeds overnight.
2. Drain the excess water and cover the seeds with wet cloth. Leave them for a day.
3. Keep sprinkling water at regular intervals so that they do not dry up.
4. Open the seeds carefully and observe the parts.

Observation: The seed is germinated i.e., the seed embryo is developed into seedling plumule which grows into plant.

Activity – 5

Observe different stages of mitotic cell division. (OR)
Describe various stages of mitosis with the help of neat diagrams.
Answer:

1. Take permanent slides which shows different stages of mitotic cell division from your lab kit.
2. Observe carefully under microscope.
3. Draw diagrams what you observe, and compare your observations with the following chart.

Stage	Description
1. Prophase	Chromosomes contract, spiral and become visible even in light microscope and nucleoli become smaller (material to chromosomes). Chromosomes split lengthwise to form chromatids, connected by centromeres. Nuclear membrane disappears. Centrosome, containing rod-like centrioles, divides and forms ends of spindle (probably animal cells only). (Note : No pairing of chromosomes as in meiosis).
2. Metaphase	Chromosomes move to spindle equator, spindle fibres attached to centromeres.
3. Anaphase	Centromeres split, separating the chromatids. Spindle fibres attached to centromeres contract, pulling chromatids towards poles.
4. Telophase	Chromatids elongate, become invisible, (replication at this stage to become chromosomes). Nuclear membranes form round daughter nuclei. Cell membrane pinches in to form daughter cells (animals) or new cell wall material becomes laid down across spindle equator (plants). Nucleus divides into two and division of cytoplasm starts.