Which One of the Following Statements Is TRUE Regarding the Nitrogen

Multiple Choice

Which one of the following statements is TRUE regarding the nitrogen cycle?

A) Nitrogen fixation results in the production of nitrogen from carbon.
B) Atmospheric nitrogen cannot be used by living organisms because two nitrogen atoms are held tightly together by a triple covalent bond.
C) Plants rely on animals for their source of usable nitrogen.
D) Once nitrogen is "fixed," it must then be converted to nitrogen gas before it can be used by living organisms.
E) In a balanced ecosystem, denitrification occurs more often than nitrogen fixation.