Bacteria plays an important role in:

Explanation

In nitrogen cycle :Nitrogen-fixing bacteria convert N2 to ammoniaNitrifying bacteria convert ammonia to nitrates and nitritesDenitrifying bacteria release the N2 back to the atmosphere by converting nitrates back to atmospheric nitrogenIn the carbon cycle, bacteria decompose dead organisms and release carbon back to the environment.In the phosphorus cycle, bacteria convert phosphate into the organic form so that it can be utilized by the plants.