What are those crops called which are grown in the winter season?

Cattle husbandry is done for the following purposes:
$(i)$ Milk production
$(ii)$ Agricultural work
$(iii)$ Meat production
$(iv)$ Egg production

$A$ farmer wanted to invest some money in fish farming. But he did not get right guidance.
$(a)$ How can you guide him for a profitable business in spite of limitations of fish farming?
$(b)$ What is the limitation of fish farming?

Kavita,the science teacher,was teaching her students about the types of diseases based on duration: acute and chronic diseases. She also discussed their ability to spread in public and their immediate causes.
$(a)$ What are acute and chronic diseases? Give one example of each.
$(b)$ Name the type of diseases which spread by coming in contact with a sick person. Name the different types of organisms which cause diseases.

Write the name of a bio-fertilizer.

Jessica saw her mother rotating a milk churner in a container of milk. She was surprised and asked her mother why she was doing that. Her mother smiled and explained that she was separating cream from milk,which would be used in various dishes.
$(a)$ What kind of qualities are shown by Jessica's mother?
$(b)$ How is cream easily separated from milk by a milk churner?