$(i)$ Name the three varieties of pesticides used.
$(ii)$ Write the problems related to the excess use of pesticides.

$(i)$ List three factors on which cultivation practices and crop yield depend.
$(ii)$ Name three stages involved in farming practices.

$(a)$ Give two examples of shellfishes.
$(b)$ Mention the names of four marine fish of high economic value.

$(a)$ What is lactation period? Name two breeds of cattle which are selected for their long lactation period. Why are they crossed with local breeds?
$(b)$ What are roughage and concentrates?

Ria was studying about $DNA$ in her textbook,learning that $DNA$ molecules are responsible for constructing and organizing cells and are present as part of chromatin material in the nucleus to transfer hereditary information. Ria was confused about how she could know if she possesses all the hereditary information from her parents. Her mother explained that through their hair or cells,the $DNA$ of parents and a child can be matched.
$(a)$ What kind of qualities are shown by Ria's mother?
$(b)$ In which part of a cell is $DNA$ found? State its function.

Which one is not a source of carbohydrate?