All living organisms are made up of carbon. The carbon cycle describes the movement of carbon as it is recycled and reused throughout the atmosphere. According to the diagram, carbon is constantly being exchanged between the plants, animals, oceans and atmosphere. Which of the following provides the BEST explanation about the carbon cycle? A Carbon is removed from the ecosystem through decaying organisms. B Carbon is removed from the ecosystem through respiration. C Carbon enters the ecosystem through photosynthesis. D Carbon enters the ecosystem through respiration.