#### Answer

a.
graphical
b.
Input Description: years since 2000
Input Units: years
Output Description: iPod sales in thousands
Output Units: none
c.
function
d.
x
↓
Rule f
↓
f(x) (years)

#### Work Step by Step

a. The representation is graphic because the question provides a graph of the data.
b. The input is years and the output is iPod sales. Because if you input the year you will get the number of sales of iPods. The input units are years because that is the way of measuring it. The output is none because it is just iPods it is nut a unit.
c. The relation is a function because every year has only one number for sales.
d. Draw an input/output diagram of the data.