Question

1. the two most abundant gases in the atmosphere are: a. water vapor & methane b. nitrogen & carbon dioxide c. oxygen & carbon dioxide d. nitrogen & oxygen

Explanation:

To determine the two most abundant gases in the atmosphere, we recall atmospheric composition: Nitrogen ($N_2$) makes up about 78% and Oxygen ($O_2$) about 21% of the atmosphere. Option A has trace gases (water vapor, methane). Option B: Carbon Dioxide is a trace gas. Option C: Carbon Dioxide is trace. Option D matches the major components.

Answer:

D. Nitrogen & Oxygen