What is the role of red blood cells?

• A. Helps fight infection
• B. Helps clot the blood
• C. Carries oxygen to all parts of your body
• D. Regulates blood pressure

Answer: (C)

Red blood cells are specialized to deliver oxygen to the body's tissues. They contain hemoglobin, a protein that binds oxygen in the lungs and releases it wherever cells need it for cellular respiration and energy production. Their efficient oxygen transport is aided by their biconcave shape, which increases surface area for gas exchange, allowing oxygen to be carried to all parts of the body. While they do carry a portion of carbon dioxide back to the lungs, the primary function is oxygen delivery. This is why this option best fits the role of red blood cells. Fighting infection is the job of white blood cells, clotting involves platelets and clotting factors, and regulating blood pressure involves the heart, vessels, and kidneys, not red blood cells.