What is a unique feature of type "O" blood?

Type "O" blood is recognized as a universal donor because it lacks A and B antigens on the surface of its red blood cells. This characteristic allows type "O" blood to be safely transfused to individuals with any other blood type – A, B, AB, or O – without triggering an immune response.

When a person receives a blood transfusion, their immune system could react negatively if the donor blood contains antigens that their own blood does not recognize. Since type "O" blood does not have these antigens, it minimizes the risk of a transfusion reaction, making it suitable for all blood types.

The other options refer to characteristics that do not apply to type "O" blood. For instance, being a universal recipient pertains to type "AB" blood, which possesses both A and B antigens and can accept any blood type. Additionally, type "O" blood cannot receive blood from other types without risking a reaction, hence it cannot only receive type "O" blood. The classification of donating strictly to type "AB" does not apply, as type "O" can donate to all blood types, not just one.