Carbon dioxide is removed from the atmosphere by plants for photosynthesis. The carbon from the carbon dioxide is used to make carbohydrates, fats and proteins, which make up the body of plants.
When plants respire, some carbon dioxide is released into the atmosphere. When plants are eaten by animals, which are eaten by other animals, some carbon becomes part of the fats and protein in their bodies. When the animals respire, carbon dioxide is released into the atmosphere.
When plants and animals die, some animals feed on their bodies. When these animals respire, some carbon dioxide is released.
By the time decay is complete on dead plants and animals, all the energy originally absorbed by the plants has been transfered, Burning wood and fossil fuels also produces carbon dioxide.
carbon dioxide + water (+ light energy) -----> glucose + oxygen
glucose + oxygen -----> carbon dioxide + water (+ energy)