I just need help answering this question

G 20 22 24 26 28 The graph attached to this question has 7 consecutive intervals (AB, BC, CD, DE, EF, FG and GH). 1. During which interval(s) is the average rate of change the largest? 2. During which interval(s) is the average rate of change zero? 3. During which interval(s) is the average rate of change the smallest non-zero value? 4. What is the average rate of change between points F and H