1. Human activities |
2. Running of automobiles |
3. Consumption of fossil fuels |
A) 1 and 2
B) 2 and 3
C) 1 and 3
D) 1, 2, 3
Correct Answer: D
Solution :
The oxygen concentration in atmosphere is 21%. The oxygen cycle is effected by human activities such as running automobiles and consumption of fossil fuels which release more carbon dioxide in the atmosphere.You need to login to perform this action.
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