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 ...

Knowing your blood type is crucial medical information, but unless you've given blood before you might not be sure what yours is. I realized this when I was asked for mine while filling out paperwork ...