Nitrogen fixation
A. changes the free nitrogen (N2) to a form usable by plants
B. especially changes nitrogen compounds, mostly amines such as NH2
C. both (a) and (b)
D. fix the free nitrogen (N2) by which it should not be usable by plants
Answer:C
Nitrogen fixation
A. changes the free nitrogen (N2) to a form usable by plants B. especially changes nitrogen compounds, mostly amines such as NH2 C. both (a) and (b) D. fix the free nitrogen (N2) by which it should not be usable by plants