Plants remove carbon dioxide from the atmosphere during the process of photosynthesis.

Humans burn fossil fuels, releasing carbon oxides into the atmosphere.

Plants and animals release carbon dioxide into the atmosphere during respiration.

Carbon dioxide is exchanged between the air and the ocean.

Ancient animals and plants eventually become fossil fuels, such as coal.

Decomposers transform organic matter into carbon and return it back to the soil.

Some ocean animals use the carbon in the water to make their shells.

Carbon used from the shells of ocean creatures form limestone in the ocean sediment.