Mention any two abiotic factors that affect crop production.

$A$ 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?

The changes brought by biotic and abiotic factors in food grains that are not stored properly include:

Poultry fowl are susceptible to the following pathogens:

Find out the correct sentence:
$(i)$ Hybridisation means crossing between genetically dissimilar plants.
$(ii)$ Cross between two varieties is called as inter-varietal hybridisation.
$(iii)$ Introducing genes of desired character into a plant gives genetically modified crop.
$(iv)$ Cross between plants of two species is called as inter-specific hybridisation.

The level of vitamins $A$ and $K$ is kept high in poultry feeds.