Animal breeding is producing improved breeds of ...$A$.. by improving their ...$B$... through selective mating. Here $A$ and $B$ refer to:

Statement $X$: Humans exploit mammals for obtaining milk.
Reason $Y$: Naturally,milk is intended for the nourishment of the animal's offspring.

$A$: Bulls not selected for breeding are castrated when young and converted to bullocks. $R$: They are the main source of animal drought power in India.

Which of the following statements are the main objectives of animal breeding?
$I$. Improved growth rate
$II$. Increased production of milk,meat,egg,wool,etc.
$III$. Superior quality of milk,meat,eggs,wool,etc.
$IV$. Improved resistance to various diseases
Choose the correct option.

In the development of human civilization,which of the following has been an integral part of development from the beginning?

The most used domesticated animal by Eskimos is