When observations begin at t =0, a cell culture has 1200 cells and continues to grow according to the function p[t} = 1200.91, where p is the number of cells and t is measured in days. a. Compute p-'(th What units are associated with the derivative and what does it measure? b. On the interval [15] when is the growth rate p-'(t} the least? When is it the greatest