Which of the following is NOT a role of digestion?

The correct answer indicates that the removal of built-up carbon dioxide from tissues and its excretion in urine is not a role of digestion. Digestion primarily focuses on breaking down food into usable nutrients such as carbohydrates, proteins, fats, vitamins, and minerals.

In the context of digestive roles, the extraction of chemical energy from food (such as converting carbohydrates into sugars and fats) allows the body to utilize that energy for various functions. Similarly, the process of obtaining raw materials from food is essential for building and repairing body tissues, particularly proteins, which are vital for cellular structure and function.

Additionally, the collection of trace minerals from food serves important purposes, such as enzyme function, hormone production, and maintaining fluid balance within the body.

While the removal of carbon dioxide is a crucial physiological process, it primarily relates to cellular respiration and the respiratory system rather than digestion. Carbon dioxide is produced as a byproduct of energy production in cells and is expelled through the lungs, signifying that it is not directly involved in the digestive process itself. Thus, recognizing this distinction clarifies why carbon dioxide removal is not a role of digestion.