How do the kidneys compensate for acid-base imbalances?
by excreting bicarbonate ion by excreting h+
by reabsorbing bicarbonate ion
by reabsorbing h+ all of the above

All of the above

Explanation:

The kidneys are slower to compensate, but renal physiology has several powerful mechanisms to control pH by the excretion of excess acid or base. In response to acidosis, the tubular cells reabsorb more bicarbonate from the tubular fluid, and the collecting duct cells secrete more hydrogen and generate more bicarbonate, and ammoniagenesis leads to an increase of the NH3 buffer.  In its responses to alkalosis, the kidneys may excrete more bicarbonate by decreasing hydrogen ion secretion from the tubular epithelial cells, and lower the rates of glutamine metabolism and ammonium excretion.

The kidneys have two very important roles in maintaining the acid–base balance:

They reabsorb bicarbonate from urine.

They excrete hydrogen ions into urine.

answer; i do believe that the correct answer is ( portal of exit in the chain of transmission); good luck