In the carbon cycle, all animals must consume other organisms because
A. they can not absorb enough carbon from water.
B. they cannot absorb carbon directly from the air.
C. they are in competition with plants for available
carbon.
D. they require carbon to perform photosynthesis.

B is the anwser, I think.

Explanation:

1.  animals cannot perform photosynthesis

2. animals cannot go into competion with plants because plants are in a total different kingdom

3. Carbon is not in water,  yes there might be a charcol-carbon water filter, yet  carbon isn't in water

that is true   : ) hope this you