Question

Match the following.

	Column I		Column II
A	Free living nitrogen fixing bacteria	i	Azolla
B	Free living nitrogen fixing cyanobacteria	ii	Rhizobium, Frankia
C	Symbiotic nitrogen fixing bacteria	iii	Aulosira
D	Symbiotic nitrogen fixing cyanobacteria	iv	Azotobacter, Beijerinckia, Clostridium

• A. A→i; B→ii; C→iii; D→iv
• B. A→ii; B→i; C→iv; D→iii
• C. A→iv; B→iii; C→ii; D→i
• D. A→iii; B→iv; C→i; D→ii

Answer 1

The correct option is C A→iv; B→iii; C→ii; D→i

Biofertilisers refer to microorganisms such as bacteria, cyanobacteria, or fungi etc. which can be used in agriculture fields for the increase in crop production. Column II represents examples of such bacteria or cyanobacteria.
Azotobacter, Beijerinckia, and Clostridium are free living nitrogen fixing bacteria. They live freely in the soil and perform nitrogen fixation.
Aulosira is a free living nitrogen fixing cyanobacteria. These are blue green algae which have the property of nitrogen fixation.
Rhizobium, Frankia are symbiotic nitrogen fixing bacteria. Rhizobium is found in association with the root nodules of plants belonging to the legume family. It performs nitrogen fixation for the plants. Frankia is associated with the root nodules of several non-legume plants. It is a nitrogen fixing bacteria.