Atmospheric Oxygen (O2)

Definition

Atmospheric oxygen refers to the oxygen present in Earth's atmosphere. It makes up about 21% of our atmosphere and is essential for aerobic respiration in many organisms.

Related terms

Photosynthesis:

The process used by plants, algae, and some bacteria to convert sunlight into chemical energy (glucose) using carbon dioxide and releasing oxygen as a byproduct.

Aerobic Respiration:

A metabolic process where cells use oxygen to produce energy from food, releasing carbon dioxide as waste.

Ozone Layer: A layer in Earth's stratosphere containing high concentrations of ozone (O3). It absorbs most of the Sun's harmful ultraviolet radiation.