There are actually 4 blood forms: A, B, AB, or O. Also, blood is both Rh-constructive or Rh-detrimental. So When you've got kind A blood, It really is either A positive or perhaps a unfavorable. Which kind that you are is significant if you need a blood transfusion. As https://www.youtube.com/watch?v=buIHtQY7fCU