$A$ teacher mentioned organisms that enrich the soil with nutrients. Rahila was curious to know more about them. She searched the internet and learned about $Rhizobium$ bacteria and cyanobacteria.
$(i)$ What are bio-fertilizers?
$(ii)$ Explain how any one of the organisms mentioned above enriches the soil with nutrients.
$(iii)$ Why was Rahila curious to get more information?

(N/A) $(i)$ Bio-fertilizers are organisms that enrich the nutrient quality of the soil by fixing atmospheric nitrogen or by dissolving phosphorus.
$(ii)$ $Rhizobium$ bacteria live in the root nodules of leguminous plants. They have a symbiotic relationship with the plants,where they fix atmospheric nitrogen into organic forms that the plants can use,thereby increasing the nitrogen content of the soil.
$(iii)$ Rahila was curious because she possessed a spirit of inquiry,a concern for science,and a scientific temperament.