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NEET Biology QUESTION #7286
Question 1
One of the free-living, anaerobic nitrogen-fixers is:
  • <em>Azotobacter</em>
  • <em>Beijerinckia</em>
  • <em>Rhodospirillum</em>✔️
  • <em>Rhizobium</em>
Correct Answer Explanation
Rhodospirillum is a free-living, anaerobic, photosynthetic nitrogen-fixer (purple non-sulfur bacterium). Azotobacter and Beijerinckia are free-living but aerobic nitrogen-fixers. Rhizobium is symbiotic (lives in legume root nodules). Rhodospirillum fixes nitrogen under anaerobic conditions using light energy.