Which of the following is NOT a function of the kidney?

The function of the kidneys includes several critical processes necessary for maintaining homeostasis in the body. Among those functions are the reabsorption of nutrients, regulation of blood pH, and filtration of blood, all of which play essential roles in the body's balance of fluids, electrolytes, and overall metabolic processes.

Reabsorption of nutrients occurs in the nephron, where essential substances like glucose, amino acids, and certain ions are returned to the bloodstream after filtration. This ensures that vital nutrients are conserved and not lost in urine.

Regulation of blood pH is another crucial function of the kidneys. They help maintain acid-base balance by excreting hydrogen ions and reabsorbing bicarbonate from urine, which is essential for keeping blood pH within a narrow range.

Filtration of blood is perhaps the most fundamental role of the kidneys, where they remove waste products and excess substances from the bloodstream. This filtration process occurs in the glomeruli, where blood is filtered, and then substances are selectively reabsorbed or secreted as needed.

The removal of carbon dioxide in solution, however, is not a function of the kidneys. Instead, this process is primarily managed by the lungs, which expel carbon dioxide through respiration. Therefore, identifying this option