Question

a single contraction - relaxation cycle in a muscle fiber produces a(n)
motor unit.
action potential.
twitch.
tetanic contraction.
cramp.

Explanation:

A single contraction - relaxation cycle in a muscle fiber is defined as a twitch. A motor unit is a group of muscle fibers and a motor neuron. An action potential is an electrical signal in a neuron or muscle cell. A tetanic contraction is a sustained contraction due to repeated stimuli. A cramp is an involuntary, painful muscle contraction.

Answer:

C. twitch