Nitrogen is the most prevalent gas, making up nearly 78 percent of the Earth’s atmosphere, which amounts to 4,000 trillion tons. Nitrogen comes from sources such as decaying matter and human fertilizers added to the ground. Interestingly enough, despite it being the most prevalent gas in the atmosphere, most organisms cannot utilize nitrogen in its atmospheric state. Therefore, living organisms that require nitrogen for protein synthesis must consume nitrogen through other means.

The major constituent of the Earth's atmosphere is nitrogen, which makes up about 78% of the total volume. Oxygen is the second most abundant gas, making up about 21% of the total volume. The remaining 1% is made up of trace gases such as argon, carbon dioxide, neon, helium, and methane.

Explanation:

- Nitrogen is the most abundant gas in the Earth's atmosphere, making up about 78% of the total volume. It is a colorless, odorless, and tasteless gas that is relatively inert and does not react with other elements or compounds.
- Oxygen is the second most abundant gas in the Earth's atmosphere, making up about 21% of the total volume. It is a highly reactive gas that is essential for the survival of most living organisms, including humans.
- Carbon dioxide is a trace gas in the Earth's atmosphere, making up about 0.04% of the total volume. It is a greenhouse gas that contributes to global warming and climate change.
- Argon is a noble gas that makes up about 0.93% of the Earth's atmosphere. It is a non-reactive gas that is used in various industrial and scientific applications.
- Other trace gases in the Earth's atmosphere include neon, helium, methane, krypton, and xenon.

In summary, nitrogen is the major constituent of the Earth's atmosphere by percent, followed by oxygen and trace gases such as argon and carbon dioxide.

Definitely the answer will be B only..Have a look at this .NITROGEN-78%OXYGEN-21-22%Other gases approx -1%