The correct answer is C. Nitrogen.
Nitrogen is the most abundant gas in the Earth’s atmosphere, making up about 78% of the air we breathe. Oxygen is the second most abundant gas, making up about 21% of the air we breathe. Carbon dioxide is the third most abundant gas, making up about 0.04% of the air we breathe. Ozone is a trace gas in the Earth’s atmosphere, making up about 0.003% of the air we breathe.
Nitrogen is an essential gas for life. It is used by plants to make proteins and other organic compounds. It is also used by animals to make proteins and other organic compounds, and to breathe.
Oxygen is also an essential gas for life. It is used by cells to produce energy. It is also used by plants to produce food.
Carbon dioxide is a greenhouse gas. It traps heat in the atmosphere, which contributes to climate change.
Ozone is a gas that is found in the Earth’s stratosphere. It protects the Earth from harmful ultraviolet radiation from the sun.