In a linear relationship, the rate of change represents the constant amount by which the dependent variable (in this case, the height of the tomato plant) changes for each unit increase in the independent variable (in this case, time, measured in days).
If we denote the rate of change as \( r \), then you can say:
The height of the tomato plant increases by \( r \) centimeters per day.
The specific value of \( r \) would depend on the actual measurements Michael takes. For example, if the plant grows 2 centimeters each day, you would describe it as:
The height of the tomato plant increases by 2 centimeters per day.
You would fill in \( r \) with the actual growth rate based on Michael's observations.