Final answer:
Denitrifying bacteria convert nitrates (NO3) into nitrogen gas (N₂), therefore the correct answer is b. denitrifying. This process is part of the nitrogen cycle, which includes nitrogen fixation, nitrification, and ammonification as well.
Step-by-step explanation:
Denitrifying bacteria :
Denitrifying bacteria are responsible for the conversion of nitrates (NO3) into free nitrogen gas (N₂), which is released back into the atmosphere. Thus, the correct answer to the question is b. denitrifying. The nitrogen cycle is a fundamental process in biology that recycles nitrogen through various chemical forms. Nitrogen fixation is the conversion of atmospheric nitrogen (N₂) into ammonia by nitrogen-fixing bacteria. Nitrification is the process by which ammonia is converted first to nitrite and then to nitrate.
Ammonification refers to the decomposition process that converts organic nitrogen into ammonium (NH₄+). Finally, denitrification completes the cycle by converting nitrates back into nitrogen gas, which can return to the atmosphere. Denitrifying bacteria play a crucial role in removing excess nitrogen from ecosystems, preventing it from accumulating and causing harm to the environment.