NCERT Solutions Curiosity Chapter 2 –33End-of-chapter questions — Let us enhance our learning

Book page 31 Updated on2026-09-05

Q1.

Here are two types of seeds. What differences do you find among the roots and leaf venation of their plants? (a) Wheat (b) Kidney beans

Answer

The two seeds belong to the two great groups of plants, so their roots and leaves are different too.

	(a) Wheat	(b) Kidney beans (rajma)
Number of cotyledons in the seed	One (the grain does not split into halves)	Two (the soaked seed splits into two halves)
Group	Monocotyledon (monocot)	Dicotyledon (dicot)
Type of root	Fibrous roots — a bunch of thin roots of similar size from the base of the stem	Taproot — one thick main root with small side roots
Leaf venation	Parallel venation — veins run side by side	Reticulate venation — a net of veins on both sides of a thick middle vein
Depth of roots	Spread near the surface, holding the top soil	Goes deep, reaching water lower down

Why the seed decides everything else: the number of cotyledons is fixed the moment the seed is formed, and the same body plan then builds the roots and the leaves. So a one-cotyledon seed always gives parallel venation and fibrous roots, and a two-cotyledon seed always gives reticulate venation and a taproot.

Check it yourself: soak a few wheat grains and a few rajma seeds overnight. The rajma splits into two halves in your fingers; the wheat grain does not. Then grow both on wet cotton for a week and look at the roots — a bunch of equal threads under the wheat, one strong central root under the rajma.

Q2.

Names of some animals are given below. Group them based on their habitats. Write the names of aquatic animals in the area marked ‘A’ and terrestrial animals in the area marked ‘B’. Enter the names of animals living in both habitats in part ‘C’. Horse, Dolphin, Frog, Sheep, Crocodile, Squirrel, Whale, Earthworm, Pigeon, Tortoise

Answer

The two circles overlap, so an animal that uses both land and water goes into the overlapping part C.

A holds animals that live only in water, B those that live only on land, and C those that use both.

Part	Animals	Reason
A — Aquatic	Dolphin, Whale	They live their whole life in water and cannot move about on land at all
B — Terrestrial	Horse, Sheep, Squirrel, Earthworm, Pigeon	They live on land — on the ground, in the soil, or on trees
C — Both	Frog, Crocodile, Tortoise	They swim in water and also come out and move about on land

Why the whale and dolphin are not in C: they come to the surface to breathe air, but they never leave the water. A frog, a crocodile and a tortoise actually walk on land — a frog hunts insects on the bank, a crocodile basks on a river bank, and a tortoise walks about on the ground. Coming up for air is not the same as living on land.

Did you know? An animal like the frog, which can live in water as well as on land, is called an amphibian.

Q3.

Manu’s mother maintains a kitchen garden. One day, she was digging out radish from the soil. She told Manu that radish is a kind of root. Examine a radish and write what type of root it is. What type of venation would you observe in the leaves of radish plant?

Answer

A radish is a taproot — a swollen main root — and the leaves of a radish plant show reticulate venation.

What you observe when you examine a radish:

There is one thick main root, white and long, tapering to a point at the lower end. This is the part we eat.
Thin side roots come out of it all along its length — you can see the tiny scars or hair-like roots on the surface.
There is no bunch of equal thin roots at the base of the stem, so it is certainly not a fibrous root system.
The leaves at the top have a thick middle vein with a net of smaller veins on both sides of it.

One main root + small side roots → Taproot
Taproot → plant is a dicot → leaves show reticulate venation

Why the radish is so thick: the radish plant stores extra food in its taproot to use later for making flowers and seeds. We harvest it before that happens — which is why the root is fat, juicy and full of food. Carrot, turnip, beetroot and sweet potato are stored in the same way.

Check it yourself: next time a bunch of radish comes home with its leaves attached, hold one leaf up to the light. The net of veins is very clear — and that alone tells you the plant is a dicot with a taproot, without digging anything up.

Q4.

Look at the image of a mountain goat and a goat found in the plains. Point out the similarities and differences between them. What are the reasons for these differences?

Answer

Both are goats, so most of the body is the same; what differs is exactly what the two habitats demand.

Similarities: both have four legs with split hooves, two horns, a small tail, hair on the body, two ears and a similar face. Both are plant eaters that graze on grass and leaves, both chew the cud, and both give birth to young ones and feed them milk.

Feature	Mountain goat	Goat of the plains	Reason for the difference
Hair / coat	Thick, long, woolly coat	Short, thin hair	The mountains are very cold; a thick coat traps warm air and keeps the body warm. In the hot plains a thin coat lets heat escape.
Body	Stout and heavily built	Slimmer and lighter	A compact body loses less heat in the cold
Legs	Shorter, thicker and stronger	Longer and slender	Short strong legs give balance and grip on steep rocky slopes; longer legs suit walking and running on flat ground
Hooves	Hard-edged with soft rough pads inside	Smoother, ordinary hooves	The rough pads act like the sole of a sports shoe and stop the goat slipping on rock

The reason behind all of it: these are adaptations — special features that enable an animal to survive in its own region. The mountain goat's region is cold, steep and rocky, so its body is built for warmth and grip. The plains goat's region is warm and flat, so its body is built for keeping cool and moving fast. Exactly the same thing happened with the camels of the hot and the cold desert on pages 25–26.

Did you know? The soft undercoat of the mountain goats of Ladakh is combed out each spring and woven into pashmina — one of the warmest and finest wools in the world. The goat grew it to survive the winter; we borrow it.

Q5.

Group the following animals into two groups based on any feature other than those discussed in the chapter—cow, cockroach, pigeon, bat, tortoise, whale, fish, grasshopper, lizard.

Answer

The chapter has already used habitat, movement, food and colour, so we must pick something else. Here is the clearest one.

Basis chosen: presence or absence of a backbone.

Group 1 — animals with a backbone	Group 2 — animals without a backbone
Cow, pigeon, bat, tortoise, whale, fish, lizard	Cockroach, grasshopper

Two other correct answers, each with a different basis:

Basis	Group 1	Group 2
How young ones are produced	Give birth to young ones — cow, bat, whale	Lay eggs — cockroach, pigeon, tortoise, fish, grasshopper, lizard
Number of legs	Six legs — cockroach, grasshopper	Four legs — cow, bat, tortoise, lizard; two legs — pigeon; no legs — whale, fish
Body covering	Hair — cow, bat, whale; feathers — pigeon	Scales — fish, lizard; hard shell — tortoise; hard outer case — cockroach, grasshopper

What makes a grouping correct: two tests. First, the basis must be a single clear feature that can be checked. Second, every animal in the list must fall into exactly one group — none left out, none in both. Both the backbone grouping and the egg-laying grouping pass these tests, so both are right. Grouping by "useful or not useful to us" would fail, because it changes from person to person.

Q6.

As the population grows and people want more comfortable lives, forests are being cut down to meet various needs. How can this affect our surroundings? How do you think we can address this challenge?

Answer

Cutting forests damages the habitat of thousands of plants and animals, and the harm reaches us too.

How it affects our surroundings:

Loss of habitat and biodiversity. Animals lose their home, food and shelter. This is exactly why the Bengal Tiger, the Cheetah and the Great Indian Bustard declined in India.
Soil erosion and landslides. Roots hold the soil. Once the trees go, rain washes the topsoil away and hillsides slip.
Less rain and hotter days. Trees give out water vapour and shade. Where forests go, the area becomes hotter and drier.
Floods and dry wells. Forest soil soaks up rain like a sponge; bare ground lets it rush off at once, so rivers flood in the monsoon and the water table falls in summer.
More carbon dioxide and polluted air. Trees take in carbon dioxide and give out oxygen. Fewer trees means dirtier air and a warmer climate.
Animals entering villages. With no food in the forest, elephants and leopards come into fields and towns, which is dangerous for both sides.
Loss of medicines and livelihoods. Many medicinal plants grow only in forests, and forest-dwelling communities depend on them for a living.

How we can address the challenge:

Plant more than we cut. Afforestation drives such as Van Mahotsav, and planting trees on every school and roadside plot.
Use less and reuse more. Write on both sides of the paper, use recycled paper and cloth bags, and avoid wasting wooden and paper goods.
Use alternatives. LPG or solar cookers instead of firewood; bamboo and agricultural waste instead of forest timber.
Protect what remains. Support national parks, sanctuaries and projects such as Project Tiger, and protect community forests and sacred groves.
Agroforestry. Grow trees along with crops on farm land so that timber and fruit come from fields, not forests.
Spread awareness. The Save Silent Valley movement and the Chipko movement succeeded because ordinary people spoke up — through posters, letters, seminars and petitions.

Why replanting alone is not enough: a newly planted sapling is not a forest. A forest is a whole habitat — old trees with hollows for owls, undergrowth, fallen logs, insects and soil built over centuries. It takes decades to rebuild what a day of felling destroys. That is why protecting an existing forest is far more valuable than planting a new one.

Q7.

Analyse the flowchart. What can be examples of ‘A’ and ‘B’?

Answer

Read the flowchart step by step. Start at "Plant" → "Does it have leaves?" → Yes → "Does it have reticulate venation?" Now the path splits:

Reticulate venation → Yes → A = plants with reticulate venation (dicots)
Reticulate venation → No → B = plants with leaves but parallel venation (monocots)

	A	B
What it stands for	Plants whose leaves have reticulate venation	Plants whose leaves do not have reticulate venation — they have parallel venation
Examples	Hibiscus (gudhal), mango, neem, tulsi, mustard, chana, rose, banyan, peepal, marigold, sadabahar	Banana, grass, wheat, maize, rice, sugarcane, bamboo, lemongrass, onion, coconut palm
Also true of them	Taproot; two cotyledons in the seed (dicots)	Fibrous roots; one cotyledon in the seed (monocots)

Why the chart begins with "Does it have leaves?": the venation question only makes sense for a plant that has leaves. A cactus, whose leaves are reduced to spines, would answer "No" at the first question and leave the chart altogether. A flowchart works only if each question is asked in the right order.

Try This: Extend the chart yourself. Under A add "Is the stem soft and green?" — Yes gives tulsi and tomato (herbs), No gives mango and neem (trees and shrubs). A flowchart of this kind is called a key, and biologists use exactly this method to identify unknown plants.

Q8.

Raj argues with his friend Sanjay that “Gudhal (hibiscus) plant is a shrub.” What questions can Sanjay ask for clarification?

Answer

Sanjay should ask questions that check the three features which define a shrub — height, the nature of the stem, and where the branches arise.

How tall is the plant? Is it shorter than us, about our own height, or much taller? (A shrub is of medium height.)
What is the colour of the stem — green or brown? (A shrub has a brown stem.)
Is the stem hard or soft? Can it be bent easily, or is it stiff and woody? (A shrub has a hard woody stem.)
Is the stem thick like a tree trunk, or thin? (A shrub's stem is hard but thin.)
Where do the branches arise — close to the ground or higher up on the stem? (In a shrub they branch close to the ground.)
Is there one single main stem, or many stems coming up from near the base? (A shrub has many.)
Does the stem need any support to stand? (If yes it would be a climber, not a shrub.)

Gudhal → medium height ✔ brown stem ✔ hard but thin ✔ branches near the ground ✔
So Raj is right — the gudhal (hibiscus) plant is a shrub.

Why asking is better than arguing: Sanjay's questions turn an opinion into an observation. Instead of "I think it is a shrub" versus "I think it is a tree", both boys end up looking at the same plant and checking the same four features — and then there is nothing left to argue about. This is the scientific method from Chapter 1 used in a quarrel between friends.

Tip: Compare the gudhal with a rose (also a shrub), a tomato plant (a herb) and a mango tree. Placing the doubtful plant beside a known example of each group is the quickest way to settle such a question.

Q9.

Based on the information in the table, find out examples of these plants for each group. Group A — Dicot seed, Taproot; Group B — Monocot seed, Fibrous roots. (a) What other similarities do plants of group A have? (b) What other similarities do plants of group B have?

Answer

Filling the "Examples" column of the table:

Group	Type of seed	Type of root	Examples
A	Dicot	Taproot	Gram (chana), kidney bean (rajma), mustard, pea, groundnut, mango, neem, gudhal, rose, marigold, tomato, sadabahar
B	Monocot	Fibrous roots	Wheat, maize, rice (paddy), grass, sugarcane, bamboo, banana, onion, lemongrass, coconut palm

(a) Other similarities among plants of group A:

Their seeds split into two cotyledons.
Their leaves show reticulate (net-like) venation.
Their main root goes deep into the soil, with side roots branching from it.
Their leaves are usually broad, with a stalk joining them to the stem.

(b) Other similarities among plants of group B:

Their seeds have a single cotyledon.
Their leaves show parallel venation.
Their roots are a bunch of similar thin roots from the base of the stem, spreading near the surface.
Their leaves are usually long and narrow, with the base wrapping round the stem.

Why the two lists never mix: all these features are settled together when the seed is formed. That is why a single observation is enough — see a bunch of fibrous roots under a plant and you can safely say its leaves have parallel veins and its seed had one cotyledon, even before looking.

Did you know? Almost every cereal India grows — wheat, rice, maize, jowar, bajra — is in group B, and almost every pulse — chana, arhar, moong, urad, rajma — is in group A. That is why a plate of dal-chawal is literally a monocot and a dicot on the same plate.

Q10.

Observe the labelled part of a duck in the picture given below. What differences do you observe in the feet of the duck compared to the other birds? Which activity would the duck be able to perform using this part?

Answer

The duck has webbed feet; the pigeon does not.

In the duck a flap of skin joins the toes into a single broad paddle; in the pigeon each toe is separate and ends in a claw.

	Duck	Pigeon and other birds
Toes	Joined together by a flap of skin (a web)	Free and separate, each ending in a claw
Shape of the foot	Broad and flat, like a paddle or a fan	Narrow, thin and gripping
What it is good for	Pushing against water	Gripping a branch or a wire

The activity the duck can perform: swimming (and paddling) in water. The webbed foot works like an oar — pushed backwards it spreads out and shoves a large volume of water back, driving the duck forward; brought forward again the web folds, so it meets very little resistance. The same broad foot also lets the duck walk on soft mud and wet sand without sinking.

Why the pigeon does not need them: a pigeon perches on branches, wires and ledges. It needs thin toes with claws that can curl around and grip. A webbed foot could not grip a wire at all, and a clawed foot would be almost useless for swimming. Each foot is an adaptation to the bird's own habitat.

Did you know? Swimmers wear rubber flippers for exactly the same reason — a bigger surface pushes more water back and gives more speed. Ducks had the idea first.

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