Domain, Codomain and Range of a Relation

If $R$ is a relation from $A$ to $B$, then $B$ is called 

Explain the terms domain, co-domain, and range in relation to a function.

If $A=\{1,2,3\}$ and $B=\{p,q,r\}$ $f=\left\{\right(1,p), (2,p), (3,r\left)\right\}$, then the codomain of $f$ is

Given below graph of the relation is not a function.

Given below graph of relation is a function.

Look at this graph:

check whether this relation is a function or not?

Draw the graph of $x=y^2$ and check whether this relation is a function or not?

Check the following graph represents a function or not: 

A function $\text{'}f\text{'}$ is defined by $f\left(x\right)=x-1$, where $x\in \{0,3,5\}$. Then find its co-domain.

If $R$ is a relation from $A$ to $B$, then $B$ is called 

If $R=\left\{(x,y):x,y\in Z,x^2+y^2\le 4\right\}$ is a relation defined on the set $Z$ of integers, then write domain of $R$