NCERT Solutions Curiosity Chapter 10 Chapter exercise — Let us enhance our learning

Book page 203 & 204 Updated on2026-09-05

Q1.

List the similarities and differences in life cycles of plants and animals.

Answer

Similarities

Both begin from a single small starting point — a seed in a plant, an egg or a newborn in an animal.
Both pass through several definite stages in a fixed order.
Both grow and develop, needing food, water and air throughout.
Both reach a stage where they can reproduce and produce the next generation.
Both finally die, while the kind continues through the next generation.
In both, the cycle then repeats — seeds give new plants; eggs give new animals.

Differences

	Plant	Animal
Starting stage	Seed	Egg or newborn young one
Name of the first step	Germination	Hatching or birth
Typical stages	Seed → germination → leaves → flowers → fruits with seeds	Egg → larva → pupa → adult (mosquito); egg → tadpole → froglet → adult (frog)
Place	Fixed in one spot for its whole life	Moves about; the habitat may change from water to land
Food	Makes its own food using sunlight	Depends on plants or other animals for food
Growth	Often continues throughout life	Usually stops at the adult stage
How the young is carried	Seeds are packed inside a fruit and scattered	Eggs are laid, or young ones are born and often cared for

Q2.

The table on the next page shows some data. Study the data and try to find out examples appropriate for the conditions given in the second and third columns. If you think that an example for any of the conditions given below is not possible, explain why. (Row 1: grow – No, respire – No; Row 2: grow – No, respire – Yes; Row 3: grow – Yes, respire – No; Row 4: grow – Yes, respire – Yes)

Answer

Take each row separately. Three of them have examples; one of them does not — and saying why is the real answer.

S. no.	Does it grow?	Does it respire?	Example	Remarks
1.	No	No	A stone, a chair, a bicycle, a plastic bottle, a piece of chalk	A plain non-living thing. Neither of the two processes takes place because there is no living body at all.
2.	No	Yes	A fully grown adult human being, an adult cow, an old banyan tree that has stopped increasing in height, an adult mosquito	Living. Growth in size stops once adulthood is reached, but respiration must continue every moment of life, because energy is needed all the time.
3.	Yes	No	No living example is possible. Only non-living things that seem to grow — crystals of common salt or copper sulphate in a saucer of solution, stalactites in a cave, an icicle, a sand dune, a snowball	A living being cannot grow without respiring, because the energy and materials for building new parts come from respiration. The listed things do get bigger, but only by material sticking on from outside — this is not true growth, and no respiration occurs.
4.	Yes	Yes	A child, a puppy, a bean seedling, a mango sapling, a tadpole	Living and still young. Both processes are going on together — this is the normal condition of every growing living being.

Why row 3 is the interesting one: it forces you to define growth properly. “It becomes bigger” is not enough. In a living being the new material is taken in as food, changed inside the body and built into the body itself, and this needs the energy released by respiration. In a crystal, particles simply settle on the outside. Same result to the eye, completely different process.

Q3.

You have learnt that different conditions are required for seed germination. How can we use this knowledge for proper storage of grains and pulses?

Answer

Keep away from the stored grain exactly the things a seed needs to germinate — water, air and warmth. Grains and pulses are seeds; if they germinate or grow mould in the store, they are spoilt.

What germination needs	What we do while storing	Why it works
Water / moisture	Dry the grain thoroughly in the sun before storing; store in a dry room; keep sacks on a wooden platform, away from the floor and walls; add a cloth bag of dry ash or lime in the bin	Without moisture the seed coat never softens and the embryo stays dormant
Air	Store in airtight tins, drums, bins or sealed bags; fill the container to the top	Without air the seed cannot respire, so it cannot germinate — and insects inside cannot survive either
Warmth	Keep the store cool, shaded and well ventilated; never near a stove or in the sun	Cool grain neither sprouts nor supports insects and moulds
Pests that bring moisture and damage	Mix in dried neem leaves, turmeric or dried red chillies; clean the container before filling; sun the grain again every few months	Insects and damp are kept out, so the seed stays dormant and whole

The one-line principle: a seed stays a seed as long as it is dry, cool and airtight. Every traditional Indian storage practice — the mud kothi, the metal drum with a tight lid, the sunning of dal on the terrace in April — is doing one of these three things.

Check it yourself: take two handfuls of moong. Keep one in a tightly closed dry jar and leave the other in an open bowl in a damp corner of the kitchen. After a fortnight in the monsoon, compare them. The open lot will smell musty and may even sprout.

Q4.

You have learnt that a tail is present in a tadpole but it disappears as it grows into a frog. What is the advantage of having a tail in the tadpole stage?

Answer

The tail is the tadpole's swimming organ. A tadpole lives entirely in water and has no legs at all in its early stage, so the tail is its only means of moving about.

What the tail lets the tadpole do:

Swim. The book says it plainly — tails help them swim in water. Side-to-side strokes of the flattened tail push the tadpole forward.
Find food. It can move around the pond to reach the algae and soft plant matter it feeds on.
Escape. A quick flick of the tail carries it away from fish, water insects and birds.
Store food. The tail is rich in stored material. When the froglet is changing and eating very little, the tail is gradually absorbed and used up — which is exactly why it seems to “disappear”.

Why the adult frog does not keep it: on land a long tail would be dead weight and would get in the way of jumping. The adult moves by powerful hops of its strong hind legs, so the tail is no longer useful. The frog does not waste it — it takes the material back into its body.

Q5.

Charan says that a wooden log is non-living as it cannot move. Charu counters it by saying that it is living because it is made of wood obtained from trees. Give your arguments in favour or against the two statements given by Charan and Charu.

Answer

The wooden log is non-living — so Charan's conclusion is right, but his reason is weak; and Charu's reason is wrong altogether.

Against Charan's reason (“it cannot move”):

Inability to move is not a proof of being non-living. A banyan tree never moves from its place and is fully alive.
The reverse is also false — a car, a river and a ceiling fan all move and none of them is living.
So movement alone can never settle the question. Charan reached the right answer by a poor argument.

Against Charu's reason (“it came from a tree”):

What matters is not where a thing came from but what it does now.
The log does not grow, does not take food, does not respire, does not excrete, does not respond to touch, heat or light, and cannot produce another log.
By the same argument, a cotton shirt (from a cotton plant), a paper page (from wood) and a leather bag would all be living — which is clearly absurd.

The correct argument:

The log was part of a living tree.
Once cut, it shows none of the characteristics of life.
→ It is non-living, because the eight life processes have stopped, not because it cannot move.

Did you know? This is the same trap as the snail's shell at the start of the chapter — but the other way round. The shell looks lifeless yet is part of a living snail; the log came from a living tree yet is now lifeless. Always test the object in front of you against all the characteristics.

Q6.

What are the similarities and distinguishing features in the life cycles of a mosquito and a frog?

Answer

Similarities

Both pass through four stages.
Both begin life as an egg laid on or near water.
In both, the young ones live in water and the adult can leave it.
Both show significant changes in appearance, body shape and structure between stages, and a change of habitat.
In both, the young one looks completely unlike the adult.
Both end with an adult that reproduces, so the cycle continues.

Distinguishing features

Point	Mosquito	Frog
The four stages	Egg → larva → pupa → adult	Egg (spawn) → tadpole → froglet → adult
Eggs	Tiny, laid singly or in small rafts directly on or near water	Hundreds together in a jelly-like cluster called spawn
Resting stage	Yes — the pupa neither feeds nor grows	No — the tadpole feeds and changes gradually throughout
How the change happens	In sudden jumps, with a complete rebuilding inside the pupa	Gradually — legs appear, then the tail shortens and disappears
Total time	About 1 to 2 weeks; the adult lives 10 to 15 days	About 14 weeks to become an adult; the adult lives for years
Adult habitat	Air and land — it flies	Both water and land
Kind of animal	An insect, with six legs and wings	An amphibian, with four legs and no wings
Effect on us	The female sucks blood and spreads malaria, dengue and chikungunya	Helpful — it eats large numbers of insects, including mosquitoes

Q7.

A plant is provided with all the conditions suitable for its growth (Fig. 10.9). Draw what you expect to see in the shoot and the root of the plant after one week. Write down the reasons.

Answer

In Fig. 10.9 the pot is lying on its side along the ground, so the seedling comes out sideways — the shoot points horizontally out of the soil and the root runs horizontally inside it.

What you should draw for “after one week”: the shoot has bent upwards near its tip and is now growing towards the sky, while the root has bent downwards and is growing into the soil below. The older, lower parts of both stay where they were, so each shows a clear bend — like the letter L.

What to draw for Question 7: after a week the shoot has bent upwards and the root downwards, even though the pot has not been moved.

Reasons

Shoots of plants grow upward and exhibit movement towards sunlight, so the shoot turns up and away from the earth to lift its leaves into the light and air where it can make food.
Roots of plants grow downwards, so the root turns down into the soil, where it can anchor the plant and take in water and minerals.
This is precisely the result of Activity 10.3, beaker B — an inverted seedling corrected itself, the root bending down and the shoot bending up. The pot lying on its side is the same test in another form.
Only the young growing region can bend, so the change shows up as a curve near the tip and not as a whole plant swinging round.

Q8.

Tara and Vijay set up the experiment shown in the picture (Fig. 10.10). What do you think they want to find out? How will they know if they are correct?

Answer

What Fig. 10.10 shows: three identical transparent containers of soil, each with one germinated seed placed in a different position.

Container	How the seedling is placed
First	Sideways — the shoot points to one side and the root to the other, both horizontal
Second	Upside down — the shoot points downwards into the soil and the root points upwards
Third	Upright — shoot up and out of the soil, root down (the normal position, used for comparison)

What they want to find out: whether the direction in which a seed is sown decides the direction in which its root and shoot grow — or whether the root always grows downwards and the shoot always upwards, no matter how the seed is placed.

How they will know if they are correct: by leaving the containers undisturbed for about a week and then looking through the transparent walls.

If in all three containers the roots have curved downwards and the shoots have curved upwards, their idea is correct — the direction of sowing does not matter.
If instead each seedling simply keeps growing in the direction it was placed, their idea is wrong.

Expected result → in every container: root bends down, shoot bends up

Why the third (upright) container matters: it is the control. It shows what a seedling does when nothing unusual is done to it. Without it, Tara and Vijay could not be sure that the bends in the other two were caused by the position and not by something else, such as the soil or the water.

Tip for your own version: use a glass tumbler with the seeds pressed against the inside wall so you can watch the root and shoot every day without digging them out. That is how the seedlings in the picture are visible at all.

Q9.

Design an experiment to check if temperature has an effect on seed germination.

Answer

Aim: To find out whether temperature affects the germination of seeds.

Materials: 40 healthy bean or gram seeds, four identical bowls or small transparent boxes, cotton wool, water, four labels, a thermometer.

Method — keep everything the same except the temperature

Line each bowl with an equal amount of cotton wool and moisten it with the same amount of water. Label them A, B, C and D.
Place 10 seeds of the same kind, size and quality in each bowl, spread out so that all of them get air.

Keep the four bowls at four different temperatures:

Bowl	Where it is kept	Approximate temperature
A	Inside a refrigerator	about 5 °C — very cold
B	In a cool, shaded corner of the room	about 15 °C — cool
C	On a shelf at ordinary room temperature (the control)	about 25–30 °C — warm
D	In a warm place such as near (not on) a stove or in a closed car in the sun	about 45–50 °C — hot

Add the same few drops of water to each bowl every day so none dries out. Keep them all in the dark, or all in the light — but the same for all four.
After 7 days, count how many seeds have germinated in each bowl and measure the length of the sprouts.

Expected results and conclusion

Bowl	Seeds germinated out of 10	What it shows
A (5 °C)	0 or 1	Too cold — the life processes in the seed are almost stopped
B (15 °C)	4 or 5, slow and short	Germination happens but is slow
C (25–30 °C)	9 or 10, healthy sprouts	Best — this is the favourable range
D (45–50 °C)	0 to 2; some seeds dry out or rot	Too hot — the embryo is damaged

Conclusion: temperature does affect germination. Seeds germinate best at a moderate, warm temperature; very low and very high temperatures reduce or stop germination.

What makes this a fair test: the seeds, their number, the cotton, the water and the light are identical in all four bowls. Only the temperature is changed. If you had also used different seeds in each bowl, you would never know which factor caused the difference. Ten seeds per bowl instead of one guards against a single dud seed spoiling the result.

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