Plants take in carbon dioxide from the air and water to make carbohydrates, some of the carbohydrates are stored in the plants tissues and then when an animal eats the plant the carbon is released into the body of the animal.

How carbon, hydrogen, oxygen, and nitrogen cycle through an ecosystem.

Carbon

Carbon is found about everywhere and is one of the biogeochemical cycles

Then when the animal breathes out the carbon is released back into the air and the process starts again.