Final answer:
When potassium channels open, hyperpolarization occurs as K+ ions exit the cell, making the inside more negative. This overshoots the resting membrane potential of -70 mV briefly until the channels close and the membrane potential returns to -70 mV. The correct answer to the question is C) hyperpolarization.
Step-by-step explanation:
When potassium channels open, the resting membrane potential, which is normally at -70 mV, experiences a change as potassium ions (K+) begin to leave the cell. During the action potential, after depolarization reaches its peak at approximately +30 mV, repolarization is initiated by the opening of potassium channels, allowing K+ to exit the cell. This outflow of positive ions hyperpolarizes the cell, causing the membrane potential to become temporarily more negative than the resting potential. Since these potassium channels are delayed in closing, there is a slight overshoot past the -70 mV resting potential. Once the K+ channels close and the sodium-potassium ATPase pump restores the ionic balance, the membrane potential returns to -70 mV, its original resting state.
The correct answer to the question is C) hyperpolarization. This occurs because, as K+ ions move out of the cell, they take positive charge with them, resulting in the internal environment of the cell becoming more negative than the resting potential until the channels close and the balance is restored.