system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: what makes different blood types different? ie; O neg. and A pos.
gpt
Different blood types are based upon things called antigens, these are found on the surface of the blood cell and help your body know the cells are your own. There are two different (major) blood cell antibodies leading to four different (major) blood groups - A, B, AB, O - A blood group has A antigens, B blood group B antigens, AB blood group has both A and B antigens and O has no antigens. The compatibility of blood groups is based on antibodies (the things that show that your antigens are your own). A antibodies attack A antigens and B antibodies attack B antigens. blood group A produce B antibodies, B produces A antibodies, AB produces no antibodies and O produces both A and B antibodies. This means that any blood group is compatible with itself as well as meaning that O is a universal donor and AB is a universal acceptor.