Which part of the cardiovascular system is primarily responsible for transporting oxygen and nutrients to tissues and removing wastes?

• A. Respiratory system
• B. Endocrine system
• C. Nervous system
• D. Cardiovascular system

Answer: (D)

The main idea is that a circulating transport system moves essential substances to every cell and removess waste from them. The cardiovascular system does this by pumping blood through a network of vessels. The heart provides the pump, arteries carry oxygen-rich blood to tissues, capillaries are the exchange sites where oxygen and nutrients move into cells and wastes move into the blood, and veins return this blood back to the heart. Oxygen bound to hemoglobin in red blood cells and dissolved nutrients travel with the plasma, while wastes like carbon dioxide are carried away to be exhaled or processed by organs such as the lungs and kidneys. While other systems support this work, they don’t perform the actual transport of oxygen, nutrients, and wastes across the body—that job belongs to the cardiovascular system.