American Indians, that is Native Americans, are a very small minority now due to numerous reasons. For starters, many of them died because of the diseases that the colonists brought with them that the natives weren't immune to, like the measles. A large amount of them died when moving westwards as they were kicked out of their land, or in the wars for defending their land. What remains is those who accepted their life in reservations at the time.
A government regulation is that the answer!!
Answer:
People with type O- blood are called universal donors because their donated red blood cells have no A, B or Rh antigens and can therefore be safely given to people of any blood group. ... Their plasma does not contain A or B antibodies and can be transfused safely to all blood types.
