Question 20 (0.75 points) √ Saved The fact that a nerve or muscle fibre responds completely or not is all is known as: the threshold level hyperpolarization negative feedback the all-or-none response an action potential

The correct answer is **the all-or-none response**.<br /><br />The all-or-none principle describes the phenomenon where a nerve or muscle fiber either responds completely to a stimulus above a certain threshold or doesn't respond at all. There's no graded response. Once the threshold is reached, the action potential fires with a fixed magnitude.<br />