What's the signifigance of the different blood types? Why is RH negative so rare and needed?

If you are anemic you feel weak and become easily tired because your blood does not contain enough iron. Sickle-cell anemia is a form of anemia in which many normal red blood cells take on a sickle shap and can not carry oxygen. Sickle-cell anemia is an inherited disease occuring mainly in people of African ancestry. iron is a strong, hard metal used to make such things as gates and railings. It is also found in some foods as well as in your body's red blood cells. What's a good source of iron for a person that's rh neg and anemic?