Together, they make up the 8 main blood groups. The 2 main ways to classify blood groups are the ABO system and the Rh system. Floating in the plasma are the red blood cells that carry oxygen, the white cells that form part of the immune system, and clotting cells called platelets. The bulk of your blood is made up of plasma.
The blood carries oxygen and nutrients to every cell in the body and picks up waste products (such as carbon dioxide) for removal from the body. The circulatory system consists of the heart, blood vessels and blood.
