Question

most of the earths air mass is found in the atmospheric layer closest to the earths surface. identify the second most abundant gas in this region, which comprises 21% of the air. choose 1 answer: a carbon dioxide b water vapor c nitrogen d oxygen

Explanation:

The atmospheric layer closest to the Earth's surface is the troposphere. In the troposphere, the most abundant gas is nitrogen (\(N_2\)) which makes up about \(78\%\) of the air. The second - most abundant gas is oxygen (\(O_2\)) which makes up about \(21\%\) of the air. Carbon dioxide (\(CO_2\)) is a minor component (about \(0.04\%\)), and water vapor varies in amount (usually less than \(4\%\)).

Answer:

D. oxygen