Carbon dioxide is a chemical compound composed of one carbon and two oxygen atoms.
It is often referred to by its formula CO2.
It is present in the Earth's atmosphere at a low concentration and acts as a greenhouse gas.
In its solid state, it is called dry ice.
It is a major component of the carbon cycle.
Atmospheric carbon dioxide derives from multiple natural sources including volcanic outgassing, the combustion of organic matter, and the respiration processes of living aerobic organisms; man-made sources of carbon dioxide come mainly from the burning of various fossil fuels for power generation and transport use.
It is also produced by various microorganisms from fermentation and cellular respiration.
Plants convert carbon dioxide to oxygen during a process called photosynthesis, using both the carbon and the oxygen to construct carbohydrates.
In addition, plants also release oxygen to the atmosphere, which is subsequently used for respiration by heterotrophic organisms, forming a cycle.