Organisms need nutrients in order to:
a. utilize hydrogen and oxygen.
b. carry out essential life functions.
c. recycle chemical compounds.
d. carry out nitrogen fixation.

The answer is letter B.

Organisms need nutrients to carry our essential life functions. These nutrients provided the necessary energy to power the different processes of the cells of the body. As a result, essential life functions are easily performed. A deficiency in one or may different nutrients in the body could result to different diseases or disorders. The main source of nutrients of the human body come from different food sources (e.g. plants, animals). These foods when broken down in the body release chemicals that are necessary for many internal processes.