Answer:
By acting as decomposer
Explanation:
Most of the nematodes are found in fresh water but some of them are found in soil as well. The species of nematodes such as round worm (earthworm) living in soils have the ability to feed on dead organic matter and release their carbon into soil thereby converting carbon within them into some usable form. These roundworm also feed on micro organisms such as bacteria, fungi and protozoa.
In a carbon cycle, the last stage requires decomposers to decompose dead and decaying organic matter and release the carbon stored in them into the soil. Since , free living nematodes (round worm) are able to do so therefore they contribute to the carbon cycle
