Question

Which best describes the movement through the nephron?

Blood is passed into the nephron and removed through the urethra.
All materials that exit the blood into the nephron are removed in the urine.
Some of the materials that exit the blood can be returned to the blood.

Answer 1

Option 3 is correct.

Reason: Blood is filtered at the glomerulus to produce a filtrate that enters the nephron, but the nephron then selectively reabsorbs useful substances (water, glucose, most salts) back into the blood and secretes additional wastes into the tubule. The remaining fluid (urine) is excreted. Thus not all materials that leave the blood end up in the urine, and blood itself is not passed through the nephron.