Final answer:
D) Blood group with D antigens in cell membranes
The Rhesus blood group is characterized by the presence or absence of the D antigen on red blood cells, with Rh-positive having the antigen and Rh-negative not. It's crucial for safe blood transfusions and in preventing hemolytic disease of the newborn in Rh- mothers with Rh+ fetuses.
Step-by-step explanation:
The Rhesus blood group system is a classification for the presence or absence of certain proteins on the surface of red blood cells. The most significant protein in this system is the D antigen. Individuals who possess this antigen are classified as Rh-positive (Rh+), while those who do not are Rh-negative (Rh-).
In terms of transfusions, the Rh Factor is crucial. Rh+ individuals can receive blood from Rh+ or Rh- donors, but Rh- individuals must only receive Rh- blood to avoid an immune response. This is important because the D antigen can provoke a significant immune reaction in those who lack it.
Additionally, the Rh Factor plays a role in pregnancy. An Rh- mother with an Rh+ fetus can develop antibodies against the D antigen, which can lead to hemolytic disease of the newborn in subsequent Rh+ pregnancies if not treated with preventive measures like RhoGAM.