In the primitive atmosphere which was not available in free state?

Options

(a) CH₄
(b) H₂
(c) O₂
(d) H₂O

Correct Answer:

O₂

Explanation:

The early atmosphere was without free oxygen, so atmosphere was reducing in nature. It only contained hydrogen, methane, ammonia and water vapours. At present free oxygen is present so atmosphere is oxidising in nature.