Final answer:
Type O negative individuals are called universal donors because their blood lacks A, B, and Rh(D) antigens, and thus does not cause an immune response when transfused into recipients with different ABO or Rh blood types. AB positive individuals are universal recipients as they can receive blood from any ABO blood type.
Step-by-step explanation:
The assertion that individuals with the blood group Type 'O' are called universal donors is indeed correct. Type O negative blood is considered the universal donor blood type because it lacks A, B, and Rh(D) surface antigens, thus it can be given to people with any ABO and Rh blood type without risking an antibody reaction. This lack of antigens means that it cannot cause the agglutination (clumping) of blood that occurs when the antibodies in the recipient's blood plasma attack the antigens on the transfused red blood cells.
Individuals with type AB positive blood are known as universal recipients because they have both A and B antigens on their red blood cells and do not have anti-A or anti-B antibodies in their plasma, allowing them to receive blood from any ABO blood type.
In summary, Type O negative individuals are called universal donors because their blood can be transfused to any other ABO and Rh blood type, and this suitability for donation does not depend on the presence of a specific reason but rather the absence of A, B, and Rh(D) antigens on the red blood cells.