Correct Answer: conversion of molecular nitrogen to ammonia

Solution : The correct option is the conversion of molecular Nitrogen to Ammonia .

Nitrogen fixation turns atmospheric molecular nitrogen (N ₂ ) into ammonia (NH ₃ ) or similar chemicals that plants and other organisms may utilise. This conversion is critical because molecular nitrogen is very inert, and cannot be directly used by most living organisms. This process can occur naturally, and artificially, including different nitrogen-fixing microorganisms, lightning, and human actions like fertilisation.