Carbon dioxide is a by-product of respiration ] and combustion combustion: Combustion is the process of burning by fire. . Green plants remove carbon dioxide from the atmosphere by photosynthesis. Living organisms-including all plants and animals-release energy from their food using respiration.Respiration and combustion-burning-both release carbon dioxide into the atmosphere.These processes form a carbon cycle in which the proportion of carbon dioxide in the atmosphere remains about the same.The animation should help you to understand how the cycle works.espiration and combustion-burning-both release carbon dioxide into the atmosphere. These processes form a carbon cycle in which the proportion of carbon dioxide in the atmosphere remains about the same.