Answer:
nitrogen fixation, nitrification, and denitrification.
Step-by-step explanation:
• Nitrogen fixation involves converting atmospheric nitrogen into the soil by nitogen fixing bacteria to form ammonia.
• Nitrification involves converting ammonia to nitrites then to nitrates by bacteria [ nitro cocci, nitrobacter and nitrospina ]
• Denitrification is the final process that involves nitrates back to atmospheric nitrogen.