Final answer:
Muscle cells need to be under voluntary control for rapid response to stimuli, maintenance of posture, and energy conservation.
Step-by-step explanation:
Most muscle cells need to be under voluntary control for rapid response to stimuli, maintenance of posture, and energy conservation.
When muscle cells are under voluntary control, they can respond quickly to stimuli, such as a predator jumping out, and move the body away from danger.
Additionally, voluntary control allows for the maintenance of posture, such as keeping the body upright while sitting or standing.
Lastly, muscle cells under voluntary control can conserve energy by only contracting when necessary.