For each relation, decide whether or not it is a function.
Domain
sky
tree
leaf
cloud
Function
Not a function
Relation 1.
Function
Not a function
Range
7
Relation 3
{(m, m),(m, d),(v, v), (v, r)}
Domain
-2
Function
Not a function
Relation 2
Function
Not a function
Range
Relation 4
{(4, z),(4, e), (3, f), (9, z)}