Question

quiz
question 6 of 10
what happens just before nitrogen reenters the atmosphere?
choose one option
a its excreted as waste by organisms.
b its stripped of any oxygen molecules.
c its converted into ammonia.
d its consumed by bacteria.

Explanation:

To solve this, we analyze the nitrogen cycle. Denitrifying bacteria convert nitrates (with oxygen - containing groups) back to nitrogen gas ($N_2$) for release into the atmosphere. This process involves stripping oxygen from nitrogen - containing compounds. Option A: Excretion of nitrogen - containing waste (like urea) is part of the cycle but not the step before re - entering the atmosphere. Option C: Conversion to ammonia is part of nitrogen fixation or ammonification, not the final step before atmospheric re - entry. Option D: Bacteria consuming nitrogen - containing compounds is part of assimilation or other steps, not the direct step before nitrogen goes back to the atmosphere. So the correct process is stripping of oxygen molecules.

Answer:

B. It’s stripped of any oxygen molecules.