Which body system is responsible for nutrient absorption?

The digestive system is responsible for nutrient absorption because it is specifically designed to break down food into its component nutrients, such as carbohydrates, proteins, and fats. This process begins in the mouth, continues in the stomach, and is finalized in the small intestine, where nutrients are absorbed into the bloodstream. The small intestine has specialized structures, such as villi and microvilli, that increase its surface area and facilitate the efficient absorption of these nutrients. Once absorbed, nutrients are transported throughout the body to provide energy, support growth, and maintain various physiological functions.

In contrast, while the respiratory system is involved in gas exchange, particularly oxygen and carbon dioxide, it does not play a role in nutrient absorption. The nervous system controls and coordinates bodily functions but does not directly participate in the digestion or absorption processes. Likewise, the endocrine system, which regulates various physiological processes through hormones, does not directly absorb nutrients but may influence how nutrients are metabolized by the body. Therefore, the digestive system is the clear and correct choice for the process of nutrient absorption.