Add Yahoo as a preferred source to see more of our stories on Google. A person's blood type is determined by "the presence or absence of certain antigens – substances that can trigger an immune ...

Blood – everyone's got it. In fact, an adult who weighs between 150 and 180 pounds has around 1.2 to 1.5 gallons of blood in their body. This makes up approximately 10% of an adult’s weight. Blood ...