The correct answer is: A. Nitrogen, oxygen
Nitrogen is the most abundant element in the Earth’s atmosphere, accounting for 78% of the volume. Oxygen is the second most abundant element, accounting for 21% of the 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. It is used by plants to create proteins and nucleic acids, and it is also used by animals to create proteins and DNA. Oxygen is also an essential element for life. It is used by cells to produce energy in the form of ATP.
Argon is a noble gas that is not reactive. It is used in light bulbs and lasers. Carbon dioxide is a greenhouse gas that contributes to climate change. Water vapor is a greenhouse gas that also contributes to climate change.
The other options are incorrect because they do not accurately reflect the composition of the Earth’s atmosphere.