NEET BIOLOGY

Detailed explanation-1: -Free-living nitrogen-fixers include the cyanobacteria Anabaena and Nostoc and genera such as Azotobacter, Beijerinckia, and Clostridium.

Detailed explanation-2: -Azotobacter is a group of Gram negative, free-living, nitrogen fixing aerobic bacteria inhabiting in the soil. They are oval or spherical in shape and form thick-walled cysts (dormant cells resistant to deleterious conditions) under unfavorable environmental conditions.

Detailed explanation-3: -Azotobacter species are free-living, nitrogen-fixing bacteria; in contrast to Rhizobium species, they normally fix molecular nitrogen from the atmosphere without symbiotic relations with plants, although some Azotobacter species are associated with plants.

Detailed explanation-4: -Azotobacter is free-living, motile, spherical bacteria that form cysts. They are aerobic and play a large role in nitrogen fixation.

Detailed explanation-5: -Nitrogen-fixing bacteria are certain bacteria that fix the nitrogen in the atmosphere and make it available to plants. Azotobacter vinelandii is a soil bacterium close to the Pseudomonas gene that fixes nitrogen in aerobic conditions and at the same time defends nitrogenase from oxygen destruction.