Nitrogen fixation is
Nitrogen $→$ Ammonia
Nitrogen $→$ Nitrates
Nitrogen $→$ Amino acids
Both $ (a) $ and $(b)$
The nitrogen fixing symbiotic organism present in Azolla is
The biofertilizer present in the roots of legumes is
Biofertilizers include
Some blue green algae can be used as biofertilizer as they are
Definitions / Explanation : Mycorrhiza