Multiple choice

Which of the following options is not free living nitrogen fixing bacteria?

  1. Anabaena

  2. Nostoc

  3. Azobacta

  4. Rhizobium

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Rhizobium is a symbiotic nitrogen-fixing bacteria that lives in root nodules of leguminous plants. Anabaena and Nostoc are free-living cyanobacteria, and Azobacta (likely Azotobacter) is a free-living soil bacteria.