What are the 2 most abundant gases in earth's atmosphere?

Answer 1

Nitrogen (N2) and oxygen (O2) are the most abundant gases in the atmosphere at 78% and 21% respectively. (78.08% Nitrogen, 20.95% Oxygen)

Related Information:

Nitrogen is important because it is a building block for life, as it is contained in amino acids and proteins.

Oxygen is important because most living organisms need it to breathe. It also is necessary for burning.

Ozone (O3) is a small component of the lower atmosphere, but is more abundant at higher altitudes. It is important because it protects life by absorbing ultraviolet radiation from the Sun. This also helps to keep Earth from getting too hot.

Water vapor (H2O) and carbon dioxide (CO2) are also present in small amounts in the atmosphere. These gases are important because they absorb heat given off by the Earth's surface. This heat absorption is largely responsible for heating the atmosphere. Without carbon dioxide and water vapor, the Earth's atmosphere would be much colder than it is.

Answer 2

Oxygen

21%