Answer:
B) nitrogen
Explanation:
There is a group of bacteria called rhizobia, which are important for the promotion of nitrogen gas in our ecosystem, through a process called biological nitrogen fixation.
This fixation is the process by which nitrogen (N2) in the atmosphere is converted into forms that can be used by plants. The reaction is catalyzed by the enzyme nitrogenase, which is found in all fixative bacteria. In terms of agriculture, the symbiosis between nitrogen-fixing bacteria (called rhizobia) and legumes (a family of plants to which soybeans, beans, peas, among others) is the most important.
This allows the nitrogen cycle to continue, in addition to allowing nitrogen to be absorbed by living beings.
