The most abundant gas in the Earth's atmosphere is:

A. carbon dioxide

B. hydrogen

C. nitrogen

D. oxygen

The most abundant gas is C. nitrogen, because nitrogen makes up 78% of earths atmosphere. the answer mostly lies mostly in three facts 1. nitrogen is volatile in most of its forms. 2. it is unreactive with materials that make up the solid earth. 3. it is very stable in the presence of solar radiation.