Nitrogen-Fixing Bacteria

Question

Nitrogen-fixing bacteria:
A)oxidize ammonia to nitrates or nitrites
B)oxidize ammonia to nitrous oxide
C)reduce nitrates to nitrites
D)reduce nitrogen gas to ammonia

Accepted Answer

Nitrogen-fixing bacteria convert atmospheric nitrogen gas (N2) into ammonia (NH3) through a process known as nitrogen fixation. This ammonia is then converted to ammonium ions (NH4+) that can be used by plants to synthesize amino acids and nucleotides. Therefore, the correct choice is D.