Final answer:
The most appropriate units for the rate of change of the temperature graph over time would be degrees Celsius per unit of time.
Step-by-step explanation:
The most appropriate units for the rate of change of the graph representing the temperature change over time would be degrees Celsius per unit of time. This is because temperature is measured in degrees Celsius, and the rate of change is determined by the change in temperature over a specific period of time. For example, if the temperature increased by 10 degrees Celsius over an hour, the rate of change would be 10 degrees Celsius per hour.