1. A plant breathes in carbon dioxide and breathes out oxygen
How do plants breathe?
A plant breathes in carbon dioxide and breathes out oxygen
through its stoma.

2. stomata

3. Stomata are tiny pores on the surfaces of leaves that permit the exchange of gases between the atmosphere and the inside of the leaf

4. Photosynthesis
At night time, plants can not make food, so they shut down by closing their stomata. 

5. Remember:
All parts of the plant breathe. -the leaves, the stem, the roots and even the flowers.
The roots of a plant also need oxygen which they obtain from the air spaces in the soil.

6. How do fish breathe?

7. GILLS The fish gills are made up of tiny flaps that are rich in blood.
Through the gills, fish are able to absorb oxygen
and give off carbon dioxide.

8. How do people breathe?

9. lungs When you breathe in, fresh air goes into your lungs.
When you breathe in (inhale) through your mouth or nose, air travels down your windpipe and into your lungs.
The lungs are
protected by the ribs
lungs

10. b. What is the amount of water vapour in the air?
Workbook p 106 2.
Label the chart to show the composition of air by percentage:
______
_____
b. What is the amount of water vapour in the air?
The amount depends on the time and place it is measured.

11. To put out a fire, we can use either or both of the following methods:
Workbook page 106
3. Fill in the blanks
To put out a fire, we can use either or both of the following methods:
Method A - Cut off the supply of oxygen.
Method B – Increase the supply of carbon dioxide
Pailin poured a bucket of sand over a small fire. Which method did
she use, A or B? Method A
__________
__________
__________
4. a. Plants can breathe only through the stomata on their leaves.
b. Sharks like seals and dolphins, need to get out of the water to
breathe.
c. Oxygen is taken into the body and carbon dioxide is removed from
the body when we breathe.
d. Water flowing out of the gills of a fish contains less oxygen than the
water entering its mouth. F F T T

12. 5. (a) Suggest why we have to come out of the water to
breathe when we are swimming although there is air
in the water?
We breathe with lungs which are
unable to take in air from water.
(b) How does a snorkel help us to swim underwater?
A snorkel has a tube that sticks out of
the water surface to get air.

13. Across Down workbook page 108 6. Complete the crossword puzzle
The organs used by humans to breathe.
Tiny holes on the underside of leaves
The gas needed for burning
Air that is moving
a. L U e. N G S
ITROGEn I T R O G E N
b. S T O M A T A
c.O X Y f.G E g.N I L S
Down
e. The gas used to make fertilizers
f. The organs used by fish to breathe
g. The organ through which air enters
or leaves a human O S E
d.W I N D

14. Breathing in: Breathing out: workbook page 109
Air rich in oxygen enters the (i)______
nose
Air goes out of the body through the (x)_____________
nose
Air goes down the (ii)_________ and into the smaller (iii) ___________
windpipe
airtubes
Air goes up the (ix)________________
windpipe
Air goes into the (iv) _________________
Air with less (viii)__________________ and richer in (vii)
____________ goes into the air tubes
lungs
carbon dioxide
(v) __________ from the air that is breathed in is taken into the bloodstream. Unwanted (vi) _______________ from the body is removed.
Oxygen
oxygen
carbon dioxide