Explain the mechanism of biological nitrogen fixation in detail

The biological nitrogen fixation is carried out by some bacte­ria, cyanobacteria and symbiotic bacteria. In symbiotic association, the bacterium provides fixed nitrogen (NH3) to the host and derives carbohydrates and other nutrients from the latter.

Biological nitrogen fixation occurs in the presence of the enzyme nitrogenase which is found inside the nitrogen fixing prokaryote. In addition to this enzyme, a source of reducing equivalents (ferredoxin (Fd) or flavodoxin in vivo), ATP and protons are required.

Explanation:

the correct answer is b