Question

Which of the organisms listed below help in nitrogen fixation?

• A. Rhizobium
• B. Blue-green algae
• C. Nitrosomonas
• D. Trypanosoma

Answer 1

Answer: (A), (B), (C)

The correct options are
A Rhizobium
B Blue-green algae
C Nitrosomonas

Rhizobium and blue-green algae help in the fixation of atmospheric nitrogen into ammonia. Nitrosomonas bacteria convert ammonia to nitrites, and Nitrobacter converts nitrites into nitrates. Hence, all these organisms contribute to nitrogen fixation. Trypanosoma, on the other hand, is a protozoan that causes sleeping sickness.