The document summarizes the carbon cycle, which is the process by which carbon atoms are recycled through biotic and abiotic parts of the environment. It involves photosynthesis by autotrophs like plants, which use carbon dioxide, water and sunlight to produce sugars and oxygen. Heterotrophs like animals then consume the sugars through cellular respiration, releasing carbon dioxide and water. Carbon is also stored both inorganically in the atmosphere, oceans, soil and organically in living things.