Because it is easy to remember.
There are really no explanations for this reason
The four blood groups are A, B, AB, and O.
The four main groups are... Group O+ (the commonest), group A+, group B+ and group AB+
There are two possibilities.... either group 'O' - or group 'B'. Also, each group can be rhesus positive or negative - making a total of four combinations.
There are four main blood groups: A, B, AB, and O. These also have a negative and a positive, I.e A+, A-, and so on. This would mean that there are eight different types of blood group: A+ A- B+ B- AB+ AB- O+ O-
The ABO blood group is the most well known blood type group. In the ABO blood group there are four types: A, B, AB and O. These blood types are determined by various combinations of two antigens and two antibodies.
If the father is homozygous for the B blood group, giving him the BB blood genotype, and the mother's genotype is AB (the only genotype for the AB blood group), then their offspring could have either the AB or B blood groups. If the father is heterozygous for the B blood group, giving him the BO genotype, then their offspring could have the AB, A, or B blood groups. However, they could not produce an offspring with the O blood group.
There is not a Blood Group AC. There is A,B,AB and O.
When the parents are with blood group AB and O, the possible blood group of the child would be either A or B. This is because the blood group AB has the genotype AB and blood group O has the genotype OO. Thus upon recombination, the only outcomes would be AO - meaning blood group A, or BO- meaning blood group B.
According to the AB0 blood group system there are four different kinds of blood groups: A, B, AB or 0 (null). Blood group A If you belong to the blood group A, you have A antigens on the surface of your red blood cells and B antibodies in your blood plasma. Blood group B If you belong to the blood group B, you have B antigens on the surface of your red blood cells and A antibodies in your blood plasma. Blood group AB If you belong to the blood group AB, you have both A and B antigens on the surface of your red blood cells and no A or B antibodies at all in your blood plasma. Blood group 0 If you belong to the blood group 0 (null), you have neither A or B antigens on the surface of your red blood cells but you have both A and B antibodies in your blood plasma.
The four blood types are A, B, AB, and O. Blood type O is the universal donor because it does not have A or B antigens on its red blood cells. Blood type AB is the universal recipient as it does not have antibodies against A or B antigens.
Blood types go into four major categories. Them being-Group A, Group B, Group AB, Group O.The most common blood type is O positive.
to blood group B and AB.