1. suppose, in performing procedure A, the test for starch and for reducing sugars both came out positive after 1- hour incubation, but after the tubes incubated for 2 hours, the test for starch came out negative. How could you explain these results?
2. suppose substance "A" is reabsorbed about 30%, whereas substance "B" is secreted about 30%. Explain how their renal plasma clearance values relate to each other and to the glomerular filtration rate (GFR).