The correct answer is: C. Nitrogen and oxygen.
Nitrogen (78%) and oxygen (21%) are the most abundant gases in the Earth’s atmosphere by volume. The remaining 1% is made up of a variety of gases, including argon, carbon dioxide, and water vapor.
Nitrogen is an essential element for life, as it is used in the formation of proteins and nucleic acids. Oxygen is also essential for life, as it is used in cellular respiration.
Argon is a noble gas that is not reactive. Carbon dioxide is a greenhouse gas that contributes to climate change. Water vapor is a greenhouse gas that also plays a role in the Earth’s climate.
The other options are incorrect because they do not list the two most abundant gases in the Earth’s atmosphere by volume.