Q. Which one is the free-living, anaerobic nitrogen-fixer?
A) $Beijernickia$
B) $Rhodospirillum$
C) $Rhizobium$
D) $Azotobacter$
Explanation
$Rhodospirillum$is a free-living, anaerobic, nitrogen fixer. Both $Beijernickia$ and $Azotobacter$ are free-living, nitrogen-fixing, aerobic microbes. $Rhizobium$is a symbiotic, nitrogen-fixer.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.