Chapter 1 - Functions - 1.1 Review of Functions - 1.1 Exercises - Page 10: 23

$V$=dependent variable $h$=independent variable Domain: [0,50]

Since the volume depends on the height of the water, $V$ is the dependent variable and $h$ is the independent variable. The domain consists of the appropriate values of $h$. Since the maximum height of the tower is 50 m, the domain is [0,50].