Final answer:
Eighty-five percent of Americans carry the positive Rh agglutinogen on their RBCs. Rh positive (Rh+) individuals have the Rh D antigen on their erythrocytes, while Rh negative individuals lack this antigen. The presence of Rh antigen is separate from a person's ABO blood group.
Step-by-step explanation:
The answer to the question is A) positive. Eighty-five percent of Americans carry the positive Rh agglutinogen on their red blood cells (RBCs). Rh blood group is determined by the presence or absence of the Rh D antigen. Approximately 85 percent of the American population have the Rh D antigen and are therefore Rh positive (Rh+). Those who do not have this antigen are Rh negative (Rh-). The presence of the Rh antigen is independent of the ABO blood group system, meaning that a person can be A, B, AB, or O and also either Rh positive or Rh negative.
When considering pregnancy, if an Rh negative mother carries an Rh positive fetus, she can become sensitized and produce anti-Rh antibodies. Without preventive treatment, a subsequent pregnancy with an Rh positive fetus could lead to hemolytic disease of the newborn due to the mother's immune response.
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