Question

Select the correct match
1. Nitrosomonas: Nitrifying bacteria
2. Rhizobia - Free-living nitrogen fixer
3. Nostoc: Free-living nitrogen fixer
4. Azotobacter: Symbiotic nitrogen fixer

• A. 1 and 3
• B. 3 and 4
• C. 2 and 3
• D. 2 and 4

Answer 1

The correct option is A 1 and 3

Nostoc: free-living nitrogen fixer(Nostoc are free-living cyanobacteria that fix nitrogen in aquatic habitats and moist soil).

Nitrosomonas: Nitrifying bacteria (Ammonia is converted to nitrates by nitrifying bacteria in the soil.)

Rhizobia: Rhizobia are bacteria that fix nitrogen (diazotrophs) after becoming established inside root nodules of legumes (symbiotic nitrogen fixers).

Azotobacter: 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.