Question

The y-axis of a graph gives the units for the?

Answer 1

The y-axis always gives the units for the dependent variable. The y-values are dependent on the x-values.

Answer 2

Answer;
Dependent variable 
The y-axis of a graph gives the units for the dependent variable.

Explanation;
Dependent variable is the variable being tested and measured in an experiment, it depends on the independent variable.
During plotting, the independent variable is placed on the horizontal axis (x-axis) and the dependent variable is plotted on the vertical axis (y-axis).