Carbon is found in living organisms. The constant flow of carbon on Earth through organisms and the air is known as the carbon cycle

True

Explanation:

Because carbon cycle is basically carbon getting recycled from one place to another. One carbon could be in human and when human dies it goes to soil. the bacteria decompose the human and release carbon as carbon dioxide and the process just repeats hence called a cycle.

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.