When we breathe in air, our body utilises the following gases:
Nitrogen, oxygen and carbon dioxide.
Nitrogen and oxygen only.
Oxygen only.
Plants only give out oxygen to the environment. It does not take in oxygen.
True
False
What is the percentage of oxygen in the air?
1%
21%
78%
Why is it an advantage to have water vapour present in the air?
The water vapour makes the air moist and not too dry for us to breathe in.
The water vapour breathed in will enter the digestive system to prevent thirst.
The water vapour will be used for respiration in the body to produce energy.
Which statement is true?
Oxygen is the only useful gas in the air for living things.
Nitrogen is the most abundant gas in the air but is useless to living things.
Carbon dioxide exists in a small percentage in the air but is useful for living things.
