Answer:
B. Nitrogen fixation
Explanation:
The following process that is illustrated by the downward arrows from the atmosphere that show the conversion of nitrogen gas into usable forms available to producers is "Nitrogen Fixation"
Nitrogen Fixation refers to the process which leads to the conversion of nitrogen in the air into ammonia (NH3) or other related nitrogenous compounds in the soil. This process is very essential because the biosynthesis of all nitrogen-containing organic compounds is as a result of the inorganic nitrogen compounds.
It is very essential and useful in agriculture.
