Which of the following processes is involved in the mechanical digestion of food?

Mechanical digestion refers to the physical processes that break down food into smaller pieces without altering its chemical structure. Peristalsis is the correct choice as it describes the rhythmic contractions of the smooth muscles in the digestive tract that propel food along the esophagus and intestines. This process plays a crucial role in mixing food with digestive juices and increasing the surface area for enzymes to act upon, facilitating more efficient digestion.

Absorption involves the uptake of nutrients through the intestinal wall into the bloodstream, which is a subsequent step after digestion rather than a process of breaking down food. Hydrolysis is a chemical reaction that involves the breakdown of compounds due to the interaction with water, primarily performed by enzymes rather than a mechanical method. Transport refers to the movement of nutrients within the body after digestion and absorption, which does not pertain to the mechanical breakdown of food itself.