In patients with severe kidney disease, urea must be removed from the blood with a "hemodialyzer." In that device, the blood passes by special membranes through which urea can pass. A salt solution ("dialysate") flows on the other side of the membrane to collect the urea and to maintain the desired concentrations of vital salts in the blood. One geometry for hemodialyzer design is with flat membranes in a rectangular system. For such a geometry, consider the following typical values: The initial removal rate of urea can be calculated as follows: 100cm1mmin60s=0.0065mingmol Suppose that your company manufactures hemodialyzers that have the characteristics described above. A colleague in the company has proposed replacing the membranes with better ones, which have the same thickness, area, and porosity but for which the urea diffusivity in the membrane is 2.7105cm2/s. a. Assuming that the average concentrations of urea in the blood and dialysate are the same as with the old membranes, by what percentage would the new membranes increase the urea removal rate? b. In terms of resistances, explain why this turns out to be such a small improvement