What is the main function of red blood cells?

• A. Transport nutrients to cells
• B. Transport carbon dioxide to lungs
• C. Transport oxygen to body tissues
• D. Repair blood vessel walls

Answer: (C)

Red blood cells, or erythrocytes, primarily function to transport oxygen from the lungs to body tissues. This is achieved through their high content of hemoglobin, a protein that binds oxygen molecules. When blood passes through the lungs, red blood cells pick up oxygen, which is then delivered to various cells and tissues throughout the body. This oxygen delivery is crucial for cellular respiration, which produces energy necessary for various cellular functions.

In addition to their primary role in oxygen transport, red blood cells also participate in the transport of carbon dioxide from the tissues back to the lungs, where it can be exhaled. However, this is not their main function. Ultimately, the focus remains on their essential role in ensuring that body tissues receive the oxygen they need to sustain life.