In which biogeochemical cycle do symbiotic bacteria in the roots of many plants play an important role

In nitrogen cycle the symbiotic bacteria in the roots of many plants play an important role.

Explanation:

During fixation of atmospheric nitrogen into ammonia various nitrogen fixing bacteria such as azobactor, clostridium forms symbiotic association with root nodules of many leguminus plants.

The root nodules of leguminus plants contain leg hemoglobin which is very much sensitive to the presence of oxygen.

Nitrogen fixation is carried out by two important enzymes reductase and nitrogenase.