How can urine contain a higher concentration of wastes (be hypertonic) than the blood?
Select one:
a. Urine cannot since the process is passive diffusion.
b. Reabsorption of water in the loop of the nephron and collecting ducts leaves behind a more concentrated urine.
c. All stages in the kidney involve active transport.
d. Urine can be hypertonic for small molecules if it is hypotonic for an equal number of big molecules.
e. The whole nephron is impermeable to water.
b. Reabsorption of water in the loop of the nephron and collecting ducts leaves behind a more concentrated urine.
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