I am erythrocytes, or otherwise known as red blood cells. I have one of the most important roles in the entire body. Out of all kinds of blood cells, I am the most numerous. My job in the body is to carry oxygen and carbon dioxide throughout the body. I contain lots of iron, which is how I transport the oxygen and carbon dioxide around. While I am floating around the blood, the iron magnetically attracts the molecules, the molecules attach to me, and then I transport them all around the body. On average, men have about 5,400,000 per cubic millimeter. …