#### Answer

The following is a sketch of a graph of the height of grass as a function of time over four weeks:

#### Work Step by Step

The height of grass is represented in the y-axis of the graph, whereas the time is represented in the x-axis. Wednesdays are specifically labeled as the question states that the grass is mowed every Wednesday afternoon.
Every Wednesday, the grass starts from some height (ie. some y-value) that the homeowner chooses to cut it to. It grows linearly over the week and reaches its peak the next Wednesday. On that day, however, it is cut again and so the y-value falls to the initial value, and so on.
The x-value is always positive since there cannot be a negative time. The y-value is always positive since there cannot be a negative height of grass, and it is not zero since the homeowner does not mow the grass until it is barren (since it keeps growing).