The rate of change in the diver's elevation can be calculated using the formula:
rate of change = (change in elevation) / (change in minutes)
Taking two points from the graph: (0, 0) and (5, -100)
Change in elevation = -100 - 0 = -100 feet
Change in minutes = 5 - 0 = 5 minutes
Rate of change = (-100 feet) / (5 minutes) = -20 feet per minute
Therefore, the rate of change in the diver's elevation is -20 feet per minute.