Why did the differential renal vein renin test show an increase in the blocked renal artery side secretion of renin, yet a drop in renin levels on the other (normal) side?

Given: For urea, the rate of excretion equals to the GFR times the urea concentration in plasma. (A) If the urea concentration in plasma is 4.5 mmol/l, what GFR (in l/day) would correspond to an excretion rate of 450 mmol/day. (B) If the urea clearance is 70 ml/min and the GFR is 125 ml/min, what fraction of urea is being reabsorbed. (answer A and B)

The presence of either protein or glucose in a urinalysis is abnormal but they end up in the urine for different reasons. For each of these molecules, briefly describe where in the urine production process (i.e., glomerular filtration, tubular reabsorption or tubular secretion) the problem occurs, and why it might happen. please help

For part A, explain why the solution inside the dialysis tubing turned blue, but the solution in the surrounding beaker did not.