Oxygen

Definition

Oxygen is a chemical element with symbol O and atomic number 8. It's essential for life on earth because it's part of the air we breathe and water we drink.

Related terms

Oxidation: The process or result of oxidizing or being oxidized; loss of electrons during a reaction by a molecule, atom or ion.

Respiration:

The process by which cells break down simple food molecules such as glucose and release the energy they contain.

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