Science 3

2. Every living thing on needs some
basic things to live and grow.

3. Basic needs of livings things
water
All living things need
water to live. Many
plants and animals
live in water.

4. air
All living things need
oxygen in the air to
breathe. Plants
need carbon dioxide
in the air to make
their food.
Needs of a Living Thing

5. food
Living things need
energy to live and
work. We get this
energy from the food
we eat.
Needs of a Living Thing

6. sunlight
It is a source of
energy. It helps the
plants to make food.
It also gives plants
and animals heat and
light.
Needs of a Living Thing

7. right temperature
Every living thing
needs a certain
temperature to grow
and live.
Needs of a Living Thing

8. The amount of these needs is
different for different types
of living things.

9. A lotus plant lives in water and
needs lots of it to grow,
while a cactus plant can survive
in deserts where there is no or
very little water.

10. All living things depend
on each other. Some
ways in which animals
depend upon plants
are:

11.  Animals depend upon
plant for food. Many
animals eat plants directly
while some eat plant-
eating animals.
 Animals depend upon
plant for oxygen.
 Many animals depend
upon plants for their
shelter.

12.  Plants depend upon
animals to spread their
seeds. The seed sticks to
the bodies of animals and
spread around as the
animals move.
 Plants depend on animals
for carbon dioxide that
they need to make their
food.

13. Human beings also depend on plants and animals. We get food
from them and other useful things like wool, honey, cotton and
wood. We also depend upon plants for oxygen.

14. Living things also
depend on many non-
living things in the
environment.

15. Human beings and
animals depend on the air
around them for the
oxygen that they need to
live. Plants also depend
on air for carbon dioxide
to make food and
nitrogen to keep them
healthy.
Air

16. All living things need
water. They depend on the
natural sources of water in
their surroundings for
different uses.
Water

17. All living things depend
on the Sun for light and
heat. Plants make food
with the help of sunlight
through process called
photosynthesis.
Sun
Photosynthesis

18. Plants depend upon soil for
growth. It provides nutrients
and water to the growing
plants. Some animals such as
rabbits, ants, snakes, and rats
depend on soil for shelter.

19. Imagine if living things
continue to live forever
and reproduce. What
will happen?

20. There would be no enough space
and we would not have enough
food. So, it is important to keep a
balance in the environment.

21. In a food chain, a
plant is eaten by an
animal who is eaten
by another animal,
and so on. This makes
sure that one type of
plant or animal does
not become to many.

22. Human beings and
animals breathe out
carbon dioxide which
is taken by plants.
Similarly, plants
produce oxygen that
we need to breathe.
Oxygen and Carbon Dioxide

23. The water cycle keeps
a balance in the levels
of water in the
environment.
water
Water heats
and goes up
Water cools
and falls back
on Earth
rain

24. Did you know?
Increasing human population and
pollution due to various human
activities are 2 major factors
affecting the balance of the
environment in today’s time.
The End 