Question

EXERCISES
A. Choose the most appropriate answer.
1. The presence of which of these components in air varies from place to place?
a. oxygen
b. nitrogen
c. carbon dioxide
d. water vapour
2. Which of these is not true for combustion?
a. Oxygen is formed.
b. Carbon dioxide is formed.
c. Oxygen is used up.
d. Nitrogen does not change.
Which of these is not an organ for taking in oxygen?
a. lungs
b. gills
c. stomata
d. atmosphere​

Answer 1

1. water vapour

3. atmosphere