Answer
The variables are Time and Grass Height.
The graph shows that the height of the grass increases over time, but at certain points in time (when the grass is mowed one can assume) there is a sudden decrease in the height of the grass. Each time the grass is cut, it is returned to its original height, and then it grows again.
Work Step by Step
Time is the variable on the x axis. Grass Height is on the y axis. A graph shows the relationship of changes in the variable on the x axis to changes in the variable on the y axis. The x axis increases as you move to the right. The y axis increases as you move up.
