A型 (Blood) refers to one of the four main blood types in the ABO blood group system. Individuals with A型 blood have A antigens on the surface of their red blood cells and produce anti-B antibodies in their plasma. This means they can receive blood from A型 and O型 donors but should not receive blood from B型 or AB型 donors. People with A型 blood are often associated with certain personality traits in popular culture, such as being organized and responsible. However, these associations are not scientifically proven. The distribution of A型 blood varies globally, with higher frequencies found in certain populations, such as those of European descent.