Why is type AB a universal blood type recipient?
it is the most common blood type of all. over one third of all people in the world have AB blood type
What are the four blood types and which is the universal donor and which is the universal recipient?
I don't think, I know. The reason the AB blood type is called the universal recipient is because people with AB type blood can receive blood from people with A, B, or O type blood - provided it's the same Rh... a person with AB positive blood could receive blood from someone with AB, A, B, or O positive blood, but not from someone with AB, A, B, or O negative blood and vice versa.
A universal donor can donate to any blood type. The only universal donor is 0 negative because it doesn't have an antigens. Antigens are things that fight off foreign objects in your body, like white blood cells. A universal recipient can receive any type of blood. The only universal recipient is AB positive.
No, any type B blood types including B positive are not universal donors or universal recipients. Type O is the universal donor as it has neither A nor B antigen on the red cells. Type O blood donors can donate blood to anyone. Type AB is the universal recipient type and can receive blood from all blood types.