Nitrogen is an essential nutrient for plant growth. But farmers who cultivate pulse crops like Green gram, Bengal gram, Black gram etc., do not apply Nitrogenous Fertilizers during cultivation. Why?​

Nitrogen is so vital because it is a major component of chlorophyll.Nitrogen is the fuel that makes plants go. It's used to synthesize amino acids, proteins, chlorophyll, nucleic acids, and enzymes. Plants need more nitrogen than any other element.Farmers who cultivate pulse crops like green gram, Bengal gram, black gram, etc. do not apply nitrogenous fertilizers during cultivation because these crops have "rhizobium bacteria".

These plants are leguminous plants and they have symbiotic relationship with Rhizobium bacteria. This bacteria converts atmosphere nitrogen in a form that the plant can use, in return the plant provide them shelter and food. That's why they don't need extra nitrogen from fertilizers.

"d.) carbon dioxide and hydrogen sulfide"

if your own plato the answer is b. the fern transitioned from sporophyte generation to gametophyte generation.