Question

The bacteria ______ supply natural manure to paddy fields.

• A. Azolla
• B. Azotobacter
  
• C. Anabaena
• D. Nostoc

Answer 1

Answer: (A)

The bacteria Azolla supplies natural manure to the paddy fields. Azolla is a gliding pteridophyte, which contains as endosymbiont the nitrogen-settling cyanobacterium Anabaena azollae (Nostocaceae family).

Generally developed in the Asian districts, Azolla is either consolidated into the dirt before rice transplanting or developed as a double product alongside rice.

So, the correct answer is A.