Question

Which statement correctly describes how nitrogen in the soil returns to the atmosphere?

Answer 1

Answer: Decomposers directly convert ammonium into nitrogen gas.

Explanation:

The living beings such as plants and animals exhibit biomolecules like nucleic acids and proteins in which the important ingredient called as nitrogen is present.  When these organisms die the dead remains of the organisms are degraded and decomposed by the soil microbes. The organic matter generated after the decomposition process consists of ammonium which is converted into nitrogen gas by the soil microbes. This way the nitrogen fixed by the soil bacteria in the soil into various forms reverts back to the atmosphere by the decomposition process.

Answer 2

The answer is "Decomposers directly convert ammonium into nitrogen gas".

Living organisms such as plants and animals contains nitrogen in the form of the amino acids and proteins. When they die, the nitrogen in the form of ammonium is decomposed by microorganisms. It is then converted into nitrites and then to nitrates by nitrifying bacteria. The denitrifying bacteria then converts nitrates into nitrogen.