For the following exercise, refer to the information given below. Round all answers to the nearest integer. In a biologyI experiment, let Mt) be the number of bacteria in a colony after 1' hours, where t - 0 corresponds to the time the experiment begins. Suppose that during the period from t - 4 hours to t - 5 hours the number of bacteria is modeled by the exponential function NU) - at. (See gure below.) 3000 2000 1000 5 b ' B N(f)-et,4st53 (a) Find the average rate of change of the population over the time period 6 S t S 7. bacteria per hour (b) What is the instantaneous rate of change of the population at t - 4 hr? At t - 4.5 hr? at t - 4 hr bacteria per hour at t - 4.5 hr bacteria per hour