Match the column $A$ with the column $B$:

Column $A$	Column $B$
$(a)$ Catla	$(i)$ Bottom feeders
$(b)$ Rohu	$(ii)$ Surface feeders
$(c)$ Mrigal	$(iii)$ Middle-zone feeders
$(d)$ Fish farming	$(iv)$ Culture fishery

Two average students, Ram and Shyam, were discussing the following graphs in the class:
[Image: $1158-196$]
The question relating to the graphs was to identify which one of them was not possible. Ram and Shyam agreed that graphs $A, B$ and $C$ were not possible. But Shyam said that graph $D$ is possible, while Ram said that it is also not possible. Since their teacher was on leave, they could not ask her. Seeing this, Ratan, who was very intelligent, came to their rescue. He told Shyam that graph $D$ was also not possible.
$(a)$ Do you think that Ratan is right? If so, why is graph $D$ not possible?
$(b)$ What values are imbibed by Ratan?

Mention two ways of obtaining fish.

Based on the kind of biological material used,what are the two kinds of manures? How are they prepared?

State three methods by which you can control the growth of weeds in agricultural fields.

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