Final answer:
Factories are not a key component of the nitrogen cycle, which includes nitrogen fixation, ammonification, nitrification, and denitrification. The false statement is that nitrification involves the conversion of nitrites to ammonium, when in fact, it is the process of converting ammonium to nitrites and then to nitrates.
Step-by-step explanation:
All of the following are key components of the nitrogen cycle except for factories. The nitrogen cycle comprises several processes including nitrogen fixation, decay (or ammonification), nitrification, and denitrification.
Nitrogen fixation can occur biotically through bacteria that live in the soil or in the root nodules of leguminous plants, as well as abiotically through natural phenomena like lightning or human activities like industrial processes.
Ammonification is the process by which organic nitrogen is decomposed by bacteria to form ammonium (NH4+). Nitrification involves the conversion of ammonium into nitrites (NO2-) and then into nitrates (NO3-), which are readily available for plant usage. Denitrification is carried out by certain bacteria that convert nitrates back into nitrogen gas (N2), releasing it into the atmosphere.
Therefore, the false statement in the given list is option d, which inaccurately states that nitrification is the process by which nitrites are converted to ammonium ion. In fact, nitrification is the reverse: the conversion of ammonium to nitrites and then to nitrates.