Question

practice it
what are the four main blood groups?
b, ab, o, d
a, b, o
a, b, ab, o
a, o, b, rh
ab, o, p, r

Explanation:

Blood groups are classified based on the presence or absence of certain antigens on red blood cells. The ABO blood group system is the most important for transfusion. In this system, the four main blood groups are determined by the combination of A and B antigens. Group A has A antigens, group B has B antigens, group AB has both A and B antigens, and group O has neither. This classification is fundamental in medicine for blood transfusions and organ transplants to avoid immune reactions.

Answer:

A, B, AB, O