1). Briefly describe the four steps in cell growth in a batch reactor. 2). Derive the cell concentration variation with time for the exponential growth period. 3). Derive the mass balance equations for cell growth and substrate consumption in a batch reactor. Ignore the lag period and use a death period. 4). Derive the mass balance equations for cell growth and substrate consumption in an ideal CSTF. Ignore the lag and death periods. 5). Graphically compare a batch and a CSTF. Justify with equations. a 6). Same graphical comparison for a combination of two reactors in series. Justify with equations