Final answer:
The functions in order from least to greatest average rates of change are g, f, h.
Step-by-step explanation:
Function g interval [2, 3] has the average rate of change of 4.
Function f interval [3, 6] has the average rate of change of 5.
Function h interval [3, 5] has the average rate of change of 8.
Therefore, the functions in order from least to greatest according to their average rates of change over intervals are g, f, h.