What is the importance of the carbon and nitrogen cycles to ecosystems?
a. they supply the energy needed for living processes.
b. they are needed to release the energy stored in food.
c. they provide materials organisms need to build their bodies.
d. they ensure that matter only moves within a nonliving environment.

The answer is letter d. They ensure that matter only moves within a nonliving environment.
Biogeochemical processes or cycles iclude carbon, oxygen, and nitrogen cycles. These cycles show the movement of elements through living and non-living components of the Earth. The gases carbon, oxygen, and nitrogen are important components of life which are pass through organisms and nonliving components,but they are never used up.

See attached file for the illustration.