NEET BIOLOGY

Detailed explanation-1: -Nitrogen returns to the soil when organisms release waste or die and are decomposed by bacteria and fungi. Nitrogen is released back to the atmosphere by bacteria get their energy by breaking down nitrate and nitrite into nitrogen gas (also called denitrification).

Detailed explanation-2: -Nitrogen is returned to the atmosphere by the activity of organisms known as decomposers. Some bacteria are decomposers and break down the complex nitrogen compounds in dead organisms and animal wastes. This returns simple nitrogen compounds to the soil where they can be used by plants to produce more nitrates.

Detailed explanation-3: -Nitrogen is an essential component of many organic molecules such as DNA, RNA and proteins, the building blocks of life. Air is the major reservoir of nitrogen that constitutes 79% of nitrogen gas (N2).

Detailed explanation-4: -Denitrification. Denitrification completes the nitrogen cycle by converting nitrate (NO3-) back to gaseous nitrogen (N2). Denitrifying bacteria are the agents of this process. These bacteria use nitrate instead of oxygen when obtaining energy, releasing nitrogen gas to the atmosphere.