RRB Group D Model Paper 10 with solutions

(2) Nitrogen fixation is a process by which nitrogen in the Earth's atmosphere is converted into ammonia (NH3) or other molecules available to living organisms. Atmospheric nitrogen or molecular dinitrogen (N2) is relatively inert: it does not easily react with other chemicals to form new compounds. Nitrogen fixation is carried out naturally in the soil by nitrogen fixing bacteria such as Azotobacter. Some nitrogen-fixing bacteria have symbiotic relationships with some plant groups, especially legumes.