Explain how red blood cells are adapted to carry out their function efficiently.

The main function of red blood cells is to transport oxygen from the lungs to tissues all across the body and to remove the waste gas product carbon dioxide from the body tissues out through the lungs.It is specially adapted to do so by their biconcave shape, which increases their surface area and therefore rapid diffusion of gases in and out. In addition, there are a lot of them to maximise oxygen transport/carbon dioxide removal and the red blood cells are relatively small in size so they can pass through capillaries easily.