Question

$N_2$ -fixing blue-green alga Anabaena which is extensively used in rice cultivation, form symbiotic association with?

• A. Cycas roots
• B. Azolla
• C. Anthoceros
• D. Alnus

Answer 1

The correct option is B Azolla

B. Azolla

Solution : The nitrogen fixing blue green algae Anabaena form symbiotic association with Azolla a kind of water floating fern. The blue green algae provides nitrogen to the fern and the fern provides habitat for the growth of algae and thus enriching the paddy fields for rice cultivation.

So the correct answer is "Azolla".