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MDCAT Biology QUESTION #11266
Question 1
Which of the following maintains the body's acid-base balance by regulating H$^+$ and HCO$_3^-$ concentrations?
  • Lungs and kidneys✔️
  • Liver and pancreas
  • Heart and lungs
  • Skin and liver
Correct Answer Explanation
The lungs regulate acid-base balance by controlling CO$_2$ excretion (which affects carbonic acid levels). The kidneys regulate it by excreting H$^+$ and reabsorbing or generating HCO$_3^-$. Together, they maintain blood pH within the narrow range of $7.35$-$7.45$.