What are the human blood groups and their antigens and antibodies?

Human blood groups are classified as A, B, AB, and O based on the presence of antigens on red blood cells and antibodies in plasma:

• Group A: A antigen, Anti-B antibody
• Group B: B antigen, Anti-A antibody
• Group AB: A and B antigens, no antibodies
• Group O: No antigens, Anti-A and Anti-B antibodies