The nitrogen cycle describes the process by which nitrogen is converted between its various chemical forms in the environment. It involves several key stages:

The nitrogen cycle describes the process by which nitrogen is converted between its various chemical forms in the environment. It involves several key stages:

• Nitrogen fixation: Atmospheric nitrogen ($\text{N}_2$) is converted into ammonia ($\text{NH}_3$) by bacteria in the soil or roots of legumes.
• Nitrification: Ammonia is converted into nitrites ($\text{NO}_2^-$) and then nitrates ($\text{NO}_3^-$) by nitrifying bacteria.
• Assimilation: Plants absorb nitrates and ammonia from the soil to synthesize proteins and nucleic acids. Animals obtain nitrogen by consuming plants or other animals.
• Ammonification: Decomposers break down dead organic matter and animal waste, releasing ammonia back into the soil.
• Denitrification: Denitrifying bacteria convert nitrates back into atmospheric nitrogen gas, completing the cycle.