Please completely answer question

6) a) Explain the difference between a function that is concave up and concave down in terms of average rate of change. b) Based on your explanation above, write the equation of a function that is neither concave up nor concave down on any interval. c) From the graph below, identify ALL sections of the graph of the function where each of the following is true: i) The function is decreasing and concave down. ii) The function is decreasing and concave up. iii) The function is increasing and concave up. iv) The function is increasing and concave down. H G