Question

d. none of these
Sale
d. variable
21
d. oxygen
A. Tick the most appropriate answer.
1. Which of the following is the major constituent of air?
a. oxygen
b. nitrogen
C. Carbon dioxide
2. What per cent of air is oxygen?
b. 38
c. 78
3. Which of the following supports combustion?
a. carbon dioxide
b. nitrogen
c. argon
4. Which of the following is necessary for photosynthesis?
a. carbon dioxide
b. methane
c. nitrogen
5. Which of the following determines climatic conditions?
a. oxygen
b. nitrogen
c. carbon dioxide
6. Which of the following is an inert gas?
a. argon
b. oxygen
c. hydrogen
7. Which metal rusts?
a. gold
b. silver
c. iron
d. oxygen
d. water vapour
d. none of these
d. aluminium​

Answer 1

Answer:

1. nitrogen

2. 21

3.

4. carbon dioxide

5. water vapour

6. argon

7. iron

Explanation:

sorry I don't know the third question.

Answer 2

Answer:

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