Limestone contains calcium carbonate which comes from animals that have shells, it already has carbon. Other sources are ocean animals which create shells that combine both carbon and calcium. Their dead bodies also release carbon to the ocean. Limestone is also known as a sedimentary rock that has carbon. Outside the ocean, limestone emits the carbon and becomes part of the carbon cycle. In addition to this, limestones are widely used by people becomes a part of the carbon cycle. Its component is present on asphalt, animal feed.