# Azolla enriches rice fields with nitrogen due to its association with

$\begin{array}{1 1}(A)\;\text{Anabaena}\\(B)\;\text{Nostoc}\\(C)\;\text{Rhizobium}\\(D)\;\text{Frankia}\end{array}$

Azolla enriches rice fields with nitrogen due to its association with anabaena
Hence (A) is the correct answer.
answered Jul 15, 2014