The Earth's carbon cycle consists of the flow, cycling, and recycling of all of the carbon on the Earth. Every living organism's composition includes the element carbon. How does carbon become part of living organisms? A.
Producers take in carbon dioxide from the air, and consumers eat the producers.

B.
Carbon is a part of sunlight and enters through the skins of all organisms.

C.
Producers take in carbon directly from the soil through their roots, and consumers eat the producers.

D.
Consumers take in carbon dioxide from the air, and producers eat the consumers.