Which of the following is a function of the digestive system?

Which of the following is a function of the digestive system?

• A. Excretion of waste
• B. Regulation of heart rate
• C. Absorption of nutrients
• D. Oxygen transport

Answer: (C)

The main idea is how the body gets nutrients from food. Absorption of nutrients is the key function described: after food is digested, nutrients pass through the lining of the small intestine into the bloodstream (and lymph) so cells can use them for energy, growth, and repair. The other options involve systems outside digestion—regulating heart rate is controlled by the nervous and circulatory systems, and oxygen transport relies on the circulatory and respiratory systems. While the digestive tract does eliminate waste, the option that most directly reflects the digestive system’s role in nourishing the body is absorbing nutrients.

The main idea is how the body gets nutrients from food. Absorption of nutrients is the key function described: after food is digested, nutrients pass through the lining of the small intestine into the bloodstream (and lymph) so cells can use them for energy, growth, and repair. The other options involve systems outside digestion—regulating heart rate is controlled by the nervous and circulatory systems, and oxygen transport relies on the circulatory and respiratory systems. While the digestive tract does eliminate waste, the option that most directly reflects the digestive system’s role in nourishing the body is absorbing nutrients.