Final answer:
If the renal clearance of acetaminophen is less than GFR, then acetaminophen must be reabsorbed.
Step-by-step explanation:
If the renal clearance of acetaminophen is less than the glomerular filtration rate (GFR), then acetaminophen must be reabsorbed in the tubules of the kidneys. The GFR represents the rate at which fluid is filtered through the glomerulus in the kidneys. Acetaminophen is typically filtered out of the blood and excreted in the urine, but if its renal clearance is less than the GFR, it suggests that some of the acetaminophen is being reabsorbed back into the bloodstream.