Answer: A. Most organisms are not able to utilize N2.
Explanation:
Nitrogen cycle is one of the important biogeochemical cycle.
Nitrogen is an ingredient for synthesis of aminoacids which are necessary for production of plant proteins. But plants are incapable of absorbing the atmospheric nitrogen directly. Certain soil bacteria convert the atmospheric nitrogen into forms like nitrites, nitrates and ammonia. This process is called as nitrogen fixation. These forms are absorbed by plants and the bacteria receives nourishment from roots of the plants.
