The chemical element with the symbol O is Oxygen.
Oxygen is a vital element for life on Earth. It is a colorless, odorless gas at room temperature and is essential for respiration in most living organisms. Oxygen makes up about 21% of the Earth’s atmosphere and is also a key component of water (H2O), which is necessary for sustaining life.
In addition to its importance in biological processes, oxygen is involved in various chemical reactions. It is highly reactive and forms compounds with almost all other elements. The most common form of oxygen is diatomic oxygen (O2), which humans and animals breathe in to produce energy.