Answer: C) Prokaryotes convert nitrogen-containing molecules into forms that can't be used by other organisms.
Prokaryotes are the organisms that do not have a membrane bound nucleus, mitochondria and other organelle. They ranges in size of diameter from 0.1–5.0 µm.
Example:<em> Escherichia coli, Sulfolobus acidocaldarius archeobacterium </em>
Decomposers, play an important role in nitrogen cycle. Nitrogen gas is converted to nitrate compound by nitrogen fixing bacteria which are present in root nodules of leguminous plants.
Example: <em>Azotobacter </em>
