Which of the following statements is NOT correct regarding the motor units and their activation?
A) A motor unit in muscles of gross movement can have thousands of muscle cells.
B) All muscle fibers in a single motor unit are of the same fiber type.
C) A weak contractile stimulus activates fast-twitch motor units.
D) The metabolic capacity of muscle fibers within a motor unit can be altered.
E) At its peak intensity, a contractile stimulus will activate muscle fibers that are easily fatigued.
Answer: : C