21%
Oxygen forms 21 percent of the Earth's atmosphere.
Oxygen is the gas that makes up about 21 percent of the Earth's atmosphere.
Earth's atmosphere is roughly 78% Nitrogen & 21% Oxygen.
Oxygen is the primary component, making up about 21% of Earth's atmosphere.
Approximately 21% of Earth's atmosphere is composed of oxygen.
Oxygen forms 21 percent of the Earth's atmosphere.
Oxygen is the gas that makes up about 21 percent of the Earth's atmosphere.
The mass percent of oxygen is approximately 21% in Earth's atmosphere.
Earth
The Earth
Oxygen composes of twenty-one percent of Earth's Atmosphere.
Earth.
Earth
oxygen
The Earth's grass produce 20 to 30 percent oxygen. The other 70 to 80 percent of oxygen is produced by marine plants.
Earth's atmosphere is roughly 78% Nitrogen & 21% Oxygen.
Oxygen is the primary component, making up about 21% of Earth's atmosphere.