Question

________ forms the symbiotic relationship with the mosquito fern, Azolla.

a) Anabaena b) Nostoc c) Azotobacter d) None of these
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Answer 1

a) Anabaena

Explanation:

Azolla and the blue-green alga Anabaena azollae maintain a symbiotic relationship: the alga provides nitrogen to the fern, and the fern provides a habitat for the alga.