What do red blood cells complement or ensure?

Red blood cells (RBCs) primarily ensure the efficient transport of oxygen from the lungs to tissues throughout the body and the return of carbon dioxide from the tissues back to the lungs for exhalation. They contain hemoglobin, a protein that binds oxygen, allowing for this critical exchange. Additionally, RBCs help maintain acid-base balance in the blood, contributing to overall homeostasis. Their unique biconcave shape also enhances their flexibility and surface area for gas exchange.