Which of the following is a nitrogen-fixing blue-green algae of soil?

A. Rhizobium
B. Nitrosomonas
C. Clostridium
D. Anabaena

Correct Answer:

Option D – Anabaena

Explanation

Anabaena is a genus of filamentous cyanobacteria that exist as plankton. They are known for nitrogen-fixing abilities, and they form symbiotic relationships with certain plants.