Why are you able to give O blood anyone?

People with type O-negative blood are known as "universal donors" because their blood can be safely transfused to people with any blood type without the risk of a major immune reaction. This is because O-negative blood lacks the A and B antigens on the surface of its red blood cells, which are the antigens that can trigger an immune response in people with other blood types. As a result, people with O-negative blood can donate their blood to anyone, regardless of their blood type.

On the other hand, people with type AB-positive blood are known as "universal recipients" because they can safely receive blood from people with any blood type without the risk of a major immune reaction. This is because AB-positive blood contains all of the A, B, and Rh antigens on the surface of its red blood cells, which means that it is not recognized as foreign by the immune system of people with other blood types.