The correct answer is D. Nitrogen.
Nitrogen is the most abundant gas in the Earth’s atmosphere, making up about 78% of the air we breathe. It is a colorless, odorless, and tasteless gas that is essential for life. Nitrogen is used by plants to create proteins and other essential molecules, and it is also used by animals to breathe.
Oxygen is the second most abundant gas in the Earth’s atmosphere, making up about 21% of the air we breathe. It is a colorless, odorless, and tasteless gas that is essential for life. Oxygen is used by plants and animals to breathe, and it is also used in combustion reactions.
Carbon dioxide is a greenhouse gas that makes up about 0.04% of the Earth’s atmosphere. It is a colorless, odorless, and tasteless gas that is produced by the burning of fossil fuels and by the respiration of animals. Carbon dioxide is a major contributor to climate change.
Hydrogen is the lightest element in the universe, and it is the most abundant element in the universe after helium. However, hydrogen is only a very small fraction of the Earth’s atmosphere, making up about 0.00005% of the air we breathe. Hydrogen is a colorless, odorless, and tasteless gas that is flammable.