Question

Which of the following is a free living aerobic
nonphotosynthetic nitrogen-fixer?
(a) Rhizobium (b) Azotobacter
(c) Azospirillum (d) Nostoc

Answer 1

Answer:

option a

Explanation:

Answer 2

Azotobacter is a free living aerobic non photosynthetic nitrogen fixer bacteria

Explanation:

Azotobacter is a spherical shaped bacteria that contain thick wall cysts and are aerobic microorganism which are unable to produce food by the help of photosynthesis.

They play an important role in nitrogen cycle as they convert the nitrogen present in the air into ammonia which is available in the soil.

More over, it is also used by human as a bio fertilizers, food additives, bio polymers etc.

Azotobacters are mainly found in neutral and basic soil and not found in acidic soil.