Denitrification reduces soil nitrates, limiting plant growth

Steps:

• Wet soil favors denitrifying bacteria growth.
• These bacteria convert soil nitrates (NO3-) to nitrogen gas (N2).
• This process depletes available nitrates in the soil.
• Plants rely on nitrates for protein synthesis and growth, so less availability stunts development.

Why A is correct:

• Denitrification removes nitrates, the form of nitrogen plants absorb, directly reducing their growth as per the nitrogen cycle.

Why the others are wrong:

• B: Waterlogged conditions inhibit nitrogen fixation, which requires oxygen; it doesn't increase.
• C: Nitrogen gas from denitrification is inert and unavailable to plants, so it doesn't promote taller growth.
• D: Fewer nitrates impair plant nutrition, causing poorer growth, not better.

Final answer: A