Question

Which of the following is a nitrogen fixing organism?

• A. Aspergillus
• B. Rhizobium
• C. Both A and B
• D. None of the above

Answer 1

The correct option is B Rhizobium

The nitrogen fixing bacteria are microorganisms present in the soil or in plant roots that change nitrogen gas from the atmosphere into solid nitrogen compounds that plants can use in the soil.
Two kinds of nitrogen fixers are recognized: free-living (non-symbiotic) bacteria and symbiotic bacteria.

Rhizobia are soil bacteria that fix nitrogen after becoming established inside root nodules of legumes.