Specifically, they are embedded within the cell membrane of RBCs. These proteins are responsible for the different blood types, such as A, B, AB, and O.

Here's a breakdown:

* Type A blood: Has the A antigen on its RBCs.

* Type B blood: Has the B antigen on its RBCs.

* Type AB blood: Has both A and B antigens on its RBCs.

* Type O blood: Does not have either A or B antigens on its RBCs.

It's important to note that the blood type proteins are not the only proteins found on RBCs. However, they are the ones responsible for determining a person's blood type and play a crucial role in blood transfusions.