All of the following statements about the nitrogen cycle are incorrect, except which?
assimilation is the process by which plants absorb and use nitrates.
nitrogen fixation is prevented by the presence of ammonium in the soil.
denitrification occurs when there’s a shortfall of available nitrogen in the soil.
the nitrogen cycle works best when bacteria are eliminated from the process.

It’s not number 3 or 4, Denitrification occurs when there’s a shortfall of available nitrogen in the soil. Or The nitrogen cycle works best when bacteria are eliminated from the process. I think its Number 1 or Assimilation is the process by which plants absorb and use nitrates.

Explanation:

the reaction mixture contains some ammonia, plus a lot of unreacted nitrogen and hydrogen. the mixture is cooled and compressed, causing the ammonia gas to condense into a liquid. the liquefied ammonia is separated and removed. the unreacted nitrogen and hydrogen are then recycled back into the reactor .