A frog muscle is stimulated with an electric current, but the muscle doesn't twitch. This probably happens because ________.
A) ionic balance has been restored
B) the synapses are underactive
C) the threshold of excitation was not reached
D) the graded potential is too great

Question

Quizplus · Accepted Answer

If the muscle doesn't twitch, it means that the threshold of excitation wasn't reached, which is when sufficient depolarization is achieved to trigger an action potential and contraction. The other options don't seem to be the cause of the lack of twitching.

A Frog Muscle Is Stimulated with an Electric Current, but the Muscle