Answer:
The correct answer is option A. "the conversion of gaseous nitrogen into an organism friendly form (ammonia (NH3)".
Step-by-step explanation:
Nitrogen fixation is a biological process at which gaseous nitrogen is converted into an organism friendly form (ammonia (NH3). Nitrogen fixation is performed in nature by microorganisms in the soil. Some of these microorganisms have a symbiotic relationship with plants. These microorganisms convert the gaseous nitrogen into ammonia, which is used by the plant as a source of nitrogen.