In the United States, 45% of the blood donated by blood donors is type O blood, which is essential in an emergency because there is no time to test the blood type of the recipient in an emergency. Type O blood is available for anyone to use. The uniqueness of type O blood is that it is consistent with all types of blood
people of all blood types can accept it, but because of its characteristics, type O blood is in short supply.
In the United States, 45% of people have blood type O, which is the common blood type for most people