Why should bee keeping be done in good pasturage?

Weeds affect the crop plants by:

Kanchan purchased gold from a jeweller. She was,however,very apprehensive about the purity of the gold purchased by her. Ultimately,she approached a person who claimed he could test its purity by making certain measurements of weight of the gold in air and water.
$(a)$ What principle was he making use of for testing purity?
$(b)$ Write the relation by which he found the relevant quantity.
$(c)$ What value did Kanchan imbibe?

$(i)$ What are weeds? Give two examples.
$(ii)$ "Removal of weeds from cultivated fields during the early stages of growth of crops is essential for a good harvest." Justify the statement.
$(iii)$ List five preventive methods that help in weed control.

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

Bakut has a poultry farm. He feeds his birds with a protein and fat-rich diet in large amounts. The birds are in good health,but their egg quality is not good.
$(a)$ What should he do to get good production of eggs?
$(b)$ What should he add in the feed to make the shells of the eggs strong?