Out of boilers and layers,which one is used to produce eggs?

Write two examples each of the fishes that are:
$(i)$ Top dwellers
$(ii)$ Middle dwellers
$(iii)$ Bottom dwellers,in composite fish culture.

$A$ little baby was playing in a park with his maid. Suddenly,he fell down and got a minor injury. The maid applied tincture of iodine on the wound.
$(a)$ Why did she apply tincture of iodine on the wound?
$(b)$ Name the solute and solvent present in tincture of iodine.
$(c)$ Enlist the values shown by the maid.

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?

Suggest some preventive measures for the diseases of poultry birds.

What do you mean by:
$(a)$ Blue revolution?
$(b)$ Yellow revolution?