(a) Why do farmers prefer biofertilisers to chemical fertilizers these days ? Explain.
(b) How do Anabaena and mycorrhiza act as biofertilizers ?

Explanation

Chemical fertilisers have significantly increased the soil pollution, reducing its quality. Therefore, farmers use biofertilisers Which enrich the quality of the soil. (b) Anabaena fix atmospheric nitrogen, thus enrich the nitrogen content of the soil in mycorrhiza, the fungal symbiont absorbs phosphorus from soil and passes it to the plant