Physiology The hyperpolarization phase of the action potential is due to? A Opening of voltage-gated Cl- channels B Prolonged opening of voltage-gated K+ channels C Closure of resting Na-t- channels D Closure of Cl- channels 💡 Explanation The hyperpolarization phase of the action potential is due to? ✓ Correct Answer: B. Prolonged opening of voltage-gated K+ channels