Which of the following functions involves the circulatory system?

• A. Regulating metabolism
• B. Transporting nutrients and oxygen
• C. Absorbing water from food
• D. Controlling body temperature

Answer: (B)

The circulatory system plays a crucial role in transporting nutrients and oxygen throughout the body. This system consists of the heart, blood vessels, and blood, which work together to deliver essential substances to tissues and organs. Oxygen is carried from the lungs to the cells where it is needed for cellular respiration, while nutrients absorbed from the digestive tract are transported via the bloodstream to support various bodily functions including energy production, growth, and repair.

While other options mention functions that involve different body systems, they do not primarily fall under the circulatory system's responsibilities. For example, regulating metabolism is mainly governed by the endocrine system, and absorbing water from food involves the digestive system. Controlling body temperature, although it can be influenced by blood flow, is primarily managed through the integumentary system and thermoregulation processes. The transportation of nutrients and oxygen is the main function that distinctly highlights the pivotal role of the circulatory system.