Question

which of the following combinations of gases were most likely the major components of the earths early atmosphere?
a. oxygen, nitrogen, hydrogen, and helium
b. hydrogen, helium, methane, and ammonia
c. nitrogen, hydrogen, and methane
d. oxygen, hydrogen, and helium

Explanation:

The Earth's early atmosphere is thought to have consisted mainly of hydrogen, helium, methane, and ammonia. These gases were present before the development of oxygen - producing life forms. Oxygen was not a major component of the early atmosphere as there was no photosynthesis to produce it.

Answer:

B. hydrogen, helium, methane, and ammonia