1) The birth rate, B, in births per hour, of a bacteria population is given in the figure below. The other curve, D, gives the death rate of the same population, in deaths per hour. bacteria/hour B D time (hours) 5 10 15 20 a) Explain what the shape of each of these graphs tells you about the population. b) Use the graphs to find the time at which the net rate of increase of the population is at a maximum. Explain your reasoning. c) At time t = 0 the population has size N. Sketch the graph of the total number born by time . Also sketch the graph of the number alive at time t. Estimate the time at which the population is a maximum. (Hint: Invent some values for the vertical scale and for N and calculate some exact figures for number of births, deaths, and current population every 5 hours. Sketch your results.)