Question

Select the ones which are correctly matched
I. Nitrosomonas – Nitrite to nitrate
II. Thiobacillus – Denitrification
III. Nostoc – symbiotic nitrogen fixer.
IV. Azotobactor – Anaerobic nitrogen fixer.

• A. I
• B. II
• C. III
• D. IV

Answer 1

The correct option is B II

Nitrate present in the soil is reduced to nitrogen by the process of denitrification. Denitrification is carried by bacteria pseudomonas and thiobacillus. A number of cyanobacteria such as anabaena and nostoc are free living nitrogen fixers. Azotobacter is free- living nitrogen fixing aerobic microbes.

Nitrosomonas and / or nitrosoccocus oxidize to nitrite help of Nitrobacteria and Nitrocystis.