Which statement about the function of red blood cells is correct?

• A. They carry oxygen to tissues.
• B. They fight infection.
• C. They form clots.
• D. They carry hormones.

Answer: (A)

The main idea is oxygen transport. Red blood cells carry oxygen from the lungs to tissues throughout the body using hemoglobin, a protein that binds oxygen where oxygen is plentiful and releases it where it’s needed for cellular respiration and energy production. They also help bring back a portion of carbon dioxide to be exhaled. Other blood components handle different jobs: white blood cells fight infection, platelets form clots to stop bleeding, and hormones travel mainly in plasma. So the statement that red blood cells deliver oxygen to tissues is the correct description of their function.