What is NOT a function of the digestive system?

The digestive system is responsible for several key functions that facilitate the breakdown and absorption of food. Secretion involves the release of digestive enzymes and other substances necessary for digestion. Mobility refers to the movement of food through the digestive tract, including peristalsis, which helps push food along. Elimination is the process of expelling waste products from the body after nutrients have been absorbed.

In contrast, filtration is not a function of the digestive system. While filtration is a process carried out by the kidneys in the urinary system to remove waste and excess substances from the blood, it does not occur in the digestive system. Hence, recognizing that filtration is primarily associated with the urinary system rather than digestion clarifies why it does not belong to the list of functions of the digestive system.