BRAINLIEST AND 50 POINTSThe domain of a relation is the output (y) values of the relation the input (x) values of the relation a set of points that pair input values with output values x and y values written in the form (x, y)

  the input (x) values of the relation

Step-by-step explanation:

The domain of a relation is the set of input values. On a graph, it is the horizontal extent of the graph. For a set of ordered pairs, the domain is the set of all first numbers in the pairs.

256π units²   (answer b)

step-by-step explanation:

the formula for the surface area of a sphere of radius r

is             a = 4πr²

and so, if r = 8 units, then the surface area is:

a = 4π(8 units)² = 256π units²   (answer b)