Q. Yield of rice is increases by :

Q. Yield of rice is increases by :

(a) Sesbania

(b) Anabaena

(c) Bacillus subtilis

(d) B. popillae

Solution :

Correct option : B 
Anabaena resides in the fronds of Azolla ( a water fern) that is grown in the rice fields to increase the efficiency of nitrogen fixation. Thus, the correct answer is B.