For any substance, Renal Clearance [ text p. 1000) is defined as the volume of plasma that is completely cleared of that substance (by the kidneys) per minute.
If the substance is freely filtered and not reabsorbed along the tubules (and no additional substance is added to the filtrate via secretion),
then renal clearance will equal GFR (125 ml/min).
a. Will renal clearance be greater or less than GFR if half of the substance is reabsorbed along the tubules ?