Question

3/10
what role do bacteria play in the nitrogen cycle?
they absorb carbon dioxide during photosynthesis
they help in the formation of dna and cell membranes
they convert nitrogen gas into nitrates and ammonia

Explanation:

• The first option is incorrect as bacteria don't perform photosynthesis (plants do).
• The second option is about the role of nitrogen in biological structures, not bacteria's role in the nitrogen cycle.
• The third option is correct: Nitrogen - fixing bacteria convert atmospheric nitrogen gas ($N_2$) into nitrates and ammonia, which is a key step in the nitrogen cycle.
• The fourth option (partially visible) is incorrect as bacteria don't regulate Earth's climate in the context of the nitrogen cycle.

Answer:

They convert nitrogen gas into nitrates and ammonia