The atmosphere of early Earth is currently thought to have contained:

A) methane, water, ammonia, nitrogen, and oxygen.
B) carbon dioxide, water, oxygen, nitrogen, and hydrogen.
C) carbon dioxide, ozone, nitric oxide, water, and hydrogen sulfide.
D) carbon dioxide, water, carbon monoxide, hydrogen, and nitrogen.
E) carbon dioxide, carbon monoxide, water, hydrogen, and nitric oxide.

Methane

A potent greenhouse gas with a chemical formula of CH4, produced by anaerobic decomposition of organic matter and widely used as a fuel.

Ammonia

Ammonia is a colorless gas with a distinct pungent smell, composed of nitrogen and hydrogen (NH3), widely used in fertilizers and as a cleaning agent.

Nitrogen

a chemical element with symbol N and atomic number 7, essential for life, making up a significant part of Earth's atmosphere.