This refers to a mapping between two sets wherein there are no two ordered pairs which have the same first element

This refers to the set of all possible values of $X$  

In functions, the $X$ values are .........

This refers to the resulting values of $Y$  

If the x values of a function has exactly one y-value, then it is called 

This refers to a mapping between two sets

True or false: All relations are functions

True or false: All functions are relations

In functions, the  $Y$ values are ..........

If the x values of a function has more than one y-value, then it is called