BLOOD!

Red Blood Cells vs. White Blood Cells

Red Blood Cells

Red blood cells are actually called Erythocytes (erytho means "red," cytes" means cell), and are often abbreviated "RBC." The main function of an RBC is to transport cells. RBCs have short lives; they only live up to four months.

White Blood Cells

White blood cells are called Leukocytes (white cell), and are abbreviated "WBC." WBCs main function is to fight disease and foreign invaders (antigens).