The carbon cycle describes the movement of carbon through Earth's biosphere, lithosphere, hydrosphere, and atmosphere. Carbon is exchanged between these carbon reservoirs through various biological, chemical, and geological processes. The key reservoirs and processes include: 1) Carbon is stored in the atmosphere, oceans, biosphere like plants and animals, and lithosphere like fossil fuels. 2) Photosynthesis uses carbon dioxide from the atmosphere and incorporates carbon into plants. Animals obtain carbon through eating plants or other animals. 3) Carbon is released back into the atmosphere through respiration by animals and plants and the burning of fossil fuels. 4) Carbon dioxide dissolves into oceans, lakes and rivers where it is used by marine plants