Answer:
Biosphere and atmosphere
Step-by-step explanation:
Carbon is an essential element and is an important element for the existence of life. The carbon cycle refers to the cyclic process by which the carbon is interchanged between the biosphere, geosphere, atmosphere, and hydrosphere.
But it mainly describes the exchange of carbon between the biosphere and the atmosphere. It is because the living organisms directly interacts with the atmosphere. The plants have the ability to consume the atmospheric carbon and in turn, releases oxygen into the atmosphere. The animals and humans are responsible for taking in the oxygen and releasing a certain amount of carbon into the atmosphere in the form of carbon dioxide.
The carbon that is stored in the plants is transferred into the body of humans and other organisms when they consume those green plants, as they obtain the organic molecules that contain organic carbon in them.
This is how the cycle repeats again and transfers the carbon from one sphere to another.