How many blood groups are there?

List all of the blood groups.How many blood groups are there?
You asked for groups and got them.
Types:
A+
A-
B+
B-
AB+
AB-
O+
O Neg
O neg is the universal donor
chief blood groups;
-classical ABO
-rhesus (Rh)
-M and N
there are 4 types
GroupA
GroupB
GroupAB
& GroupO
Type A
Type B
Type AB
Type O
And with each there is + and -
The same blood types that can donate are NOT the same types that can recieve. (see link for more on that)
there are 4 magor blood groups:
A
B
AB
O
each group can be D positive or negative, as in Apos or Oneg.
there are othe possible types of blood depending on the presence or absence of antigens in red blood cells. all these factors affect compatibility for blood transfusions.
there are four systems for classifying blood types. the 2 most commonly used are the "normal one" and Rh + and -.
have just done this in anatomy class i can tell you, while A O B and AB are the most popular, there have been over 50 identified types- the rarist being (off the top of my head) H - which only 2 people in the world are known to have.
For your purposes they would only be A, O, AB and B and - and +