Which statement about peristalsis is true?

• A. Rhythmic involuntary contractions
• B. Voluntary contractions
• C. Chemical digestion
• D. Stimulates bile

Answer: (A)

Peristalsis is the coordinated, wave‑like movement of smooth muscle in the digestive tract that propels contents forward. These contractions are rhythmic and involuntary, driven by the enteric nervous system, not under conscious control. It’s a mechanical process that moves food along, not chemical digestion. Bile release, on the other hand, is triggered mainly by chyme in the duodenum through hormones and neural signals, not directly by peristaltic waves. So the true statement is that peristalsis involves rhythmic involuntary contractions.