What process involves involuntary contractions that move food through the gastrointestinal tract?

• A. Digestion
• B. Absorption
• C. Peristalsis
• D. Metabolism

Answer: (C)

Peristalsis is the wave-like, involuntary contractions of the smooth muscles lining the gastrointestinal tract that push food and liquid forward. This coordinated squeezing moves contents from the esophagus through the stomach and into the intestines without conscious effort, kept in motion by the enteric nervous system and autonomic signals.

Digestion, by contrast, is the process of breaking food down into smaller pieces—chemically and mechanically. Absorption is the uptake of nutrients into the bloodstream or lymphatic system after digestion. Metabolism refers to the cellular chemical reactions that provide energy and build new molecules. Peristalsis specifically describes the movement of contents through the GI tract.