Which symbiotic nitrogen fixing cynaobacterium lives in associction lives in association with Azolla.

A free living nitrogen fixing cyanobacterium which can also form symbiotic association with the water fern Azolla is:

Name the best known symbiotic nitrogen fixing bacterium.

A free living anaerobic nitrogen fixing bacterium is :

Name one non-symbiotic nitrogen fixing prokaryote.

Which plants mostly help in nitrogen fixing ?

Name any one symbiotic nitrogen fixing bacteria. How does it help in nitrogen fixation ?