Which of the following is not a function that is regulated by the kidneys? A. pH of plasma B. Blood volume of plasma C. Concentration of waste and electrolytes in the plasma D. Excretion of undigested liquids in the plasma

The function that is not regulated by the kidneys from the options provided is D. Excretion of undigested liquids in the plasma.

Here's why:

A. pH of plasma: The kidneys help regulate the pH of the blood by excreting hydrogen ions into the urine and reabsorbing bicarbonate from the urine.

B. Blood volume of plasma: The kidneys regulate the volume of blood (and consequently blood pressure) by controlling the amount of water excreted in the urine. They can also produce a hormone that stimulates red blood cell production, indirectly affecting blood volume.

C. Concentration of waste and electrolytes in the plasma: The kidneys filter out waste products and excess electrolytes from the blood, helping to regulate their concentrations in the body.

D. Excretion of undigested liquids in the plasma: This is not a function of the kidneys. The process of digestion and the excretion of undigested material is primarily the responsibility of the gastrointestinal tract, not the kidneys. The kidneys filter blood, not undigested food or liquids.