When the pH of the extracellular fluid drops the kidneys do what?

When the pH of the extracellular fluid drops, indicating acidosis, the kidneys respond by increasing the excretion of hydrogen ions (H+) and reabsorbing bicarbonate (HCO3-) to help restore normal pH levels. They also produce new bicarbonate ions to further buffer the acidity. This renal compensation works alongside respiratory mechanisms to help regulate the body's acid-base balance.