Which of the following is true?

A) Muscle fatigue has no influence on the force of contractions.
B) A threshold stimulus will cause contraction of a muscle fiber.
C) A subthreshold stimulus causes a muscle contraction.
D) Motor units do not obey the "all or none" law.
E) A threshold stimulus will not affect motor units.

Threshold Stimulus

The minimum stimulus needed to cause a depolarization of the membrane and generate an action potential in excitable cells.

Muscle Fatigue

Muscle fatigue is the decline in ability of a muscle to generate force, often experienced after prolonged activity or strain.

Motor Units

A motor unit consists of a single motor neuron and all the muscle fibers it innervates, essential for muscle contraction.