Answer:
The carbonic acid-bicarbonate buffer system functions mainly to **limit changes in pH caused by metabolism**. This buffer system involves the balance of carbonic acid (H 2 CO 3), bicarbonate ion (HCO − 3), and carbon dioxide (CO 2) in order to maintain pH in the blood and other tissues, to support proper metabolic function². When any acidic substance enters the bloodstream, the bicarbonate ions neutralize the hydronium ions forming carbonic acid and water³. This system is critical for maintaining a constant blood pH, which is essential for the proper functioning of our body³. So, the correct answer would be "limit ECF pH changes caused by metabolism".
