In agricultural practices,higher input gives higher yield. Discuss how?

$(i)$ 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.

Distinguish between intercropping and mixed cropping. List any two advantages of intercropping over mixed cropping.

$A$ 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?

Poultry fowl are susceptible to the following pathogens:

Chetan's father wanted to buy a car. He visited many showrooms to find out the price and the specifications of various cars. In one of the showrooms,he was told by the salesman that their car had excellent brakes such that the car stops instantaneously. Chetan's father was impressed and decided to buy that car. In the evening,he discussed this with his family. Chetan told his father that such a car cannot be made and the salesman had lied to him. He told his father that he should not buy that car and,moreover,never from that showroom. He explained to his father why it is not possible. His father was convinced and promised to visit another showroom and be careful this time.
$(a)$ What might have been the explanation given by Chetan to convince his father?
$(b)$ What values do you see in Chetan?