Blood grouping is primarily determined by the presence of specific antigens on the surface of red blood cells (RBCs). Let's explain why the correct answer is "Antigens on RBCs" and why the other options are incorrect.
- Antigens on RBCs:
- Blood groups are categorized based on the presence or absence of specific antigens on the surface of red blood cells. The most common blood group systems are the ABO system and the Rh system.
- The ABO system classifies blood into four main types: A, B, AB, and O, depending on the specific antigens present on the RBCs.
- The Rh system further classifies blood as Rh-positive or Rh-negative, based on the presence or absence of the Rh antigen (also known as the D antigen) on the RBCs.
- MHCs on WBCs:
- MHC (Major Histocompatibility Complex) molecules are found on white blood cells (WBCs) and other tissues, primarily involved in the immune response.
- They have no role in blood grouping.
- MHCs on RBCs:
- As mentioned, MHC molecules are not present on red blood cells at all; hence, this option is incorrect.
- Antigens on WBCs:
- While white blood cells do have antigens, these antigens are not used for blood grouping. Blood grouping is exclusively based on antigens present on RBCs.
Therefore, the correct answer is indeed Antigens on RBCs as they are the crucial determinants in blood grouping based on the ABO and Rh systems.