The table shows the percentages of some substances measured in fluid taken from a human kidney.Which letter on the diagram shows the most likely source of the fluid?

Answer:

1) B

A – if it was A, there would be some protein present.
Water is reabsorbed and glucose is completely reabsorbed as we progress through the kidney. This would lead to an increase in the percentage of urea in the fluid. Since the percentage of urea is only a little, the sample must have been taken from an initial part of the nephron. Therefore, the answer is B.