Mention two advantages of animal husbandry.

In India,about $45 \%$ of the cultivated area is unirrigated,and scarce rainfall often causes crop failure,leading to drought-like conditions. This situation motivated villagers to use rainwater harvesting and watershed management.
$(i)$ What is meant by irrigation?
$(ii)$ List two different kinds of irrigation systems which can be adopted to supply water to agricultural land.
$(iii)$ What values does Rajan possess which helped villagers overcome their problem?

Two friends,Girish and Neeraj,were discussing Newton's third law. They were perplexed about how action and reaction are equal and opposite. They could not think of an experiment by which they could ascertain this fact. Pushkar,who was their friend,told them that he would set up an experiment to prove this to them. By performing an experiment,Pushkar demonstrated the law.
$(a)$ Can you think of an experiment by which you can demonstrate this law?
$(b)$ What values do you think Pushkar has?

$(a)$ What is composite fish culture system?
$(b)$ Mention one merit and one demerit of this system.

Find out the correct sentence about manure:
$(i)$ Manure contains large quantities of organic matter and small quantities of nutrients.
$(ii)$ It increases the water holding capacity of sandy soil.
$(iii)$ It helps in draining out excess water from clayey soil.
$(iv)$ Its excessive use pollutes the environment because it is made of animal excretory waste.

$(i)$ Mr. Ramdin,an educated farmer,convinces his friends to use fertilizers judiciously. Why?
$(ii)$ Which two values of Ramdin impress you?