Match the Column I with Column II :

A-2, B-1, C-4, D-3

The correct answer is Option (3)- A-2, B-1, C-4, D-3

A. Symbiotic nitrogen-fixing bacteria (2. Rhizobium): Symbiotic nitrogen-fixing bacteria, such as Rhizobium, form a mutualistic relationship with leguminous plants. They colonize the root nodules of these plants and convert atmospheric nitrogen (N2) into a form that can be utilized by the plants, such as ammonia. This process is known as biological nitrogen fixation.

B. Dragonflies (1. Mosquitoes): Dragonflies are known to be natural predators of mosquitoes. They feed on mosquitoes and help control their population in certain ecosystems. Dragonflies are known for their agile flight and excellent hunting skills, making them effective predators of mosquitoes and other small insects.

C. Bacillus thuringiensis (4. Butterfly, caterpillars): Bacillus thuringiensis (Bt) is a type of bacteria that produces protein crystals toxic to certain insect pests, especially caterpillars and some butterfly larvae. It is commonly used as a biocontrol agent in agriculture to target specific pest species while being safe for other organisms and the environment.

D. Free-living N2-fixing bacteria (3. Azotobacter): Free-living nitrogen-fixing bacteria, such as Azotobacter, are non-symbiotic bacteria that can fix atmospheric nitrogen in the soil. They convert atmospheric nitrogen into a form that can be utilized by plants and contribute to the nitrogen cycle in the ecosystem.