In denitrification, nitrogen is returned to the atmosphere as which gas?

In denitrification, nitrogen is returned to the atmosphere as which gas?

• A. Nitrogen dioxide
• B. Ammonia
• C. Molecular nitrogen
• D. Nitrous oxide

Answer: (C)

Denitrification is the process where certain bacteria use nitrate as an electron acceptor in low-oxygen conditions and reduce it through several steps until it becomes a gas that escapes into the atmosphere. The end product of this pathway is molecular nitrogen, N2, which makes up most of Earth's atmosphere. While nitrous oxide (N2O) can be produced along the way and released in some cases, the form that is ultimately returned to the atmosphere as the main product of denitrification is N2. The other gases listed are not the final end product of this process.

Denitrification is the process where certain bacteria use nitrate as an electron acceptor in low-oxygen conditions and reduce it through several steps until it becomes a gas that escapes into the atmosphere. The end product of this pathway is molecular nitrogen, N2, which makes up most of Earth's atmosphere. While nitrous oxide (N2O) can be produced along the way and released in some cases, the form that is ultimately returned to the atmosphere as the main product of denitrification is N2. The other gases listed are not the final end product of this process.