38 Mindblowing Blood Facts You Have To Know

Find out more about the 38 blood facts in our article: Blood is a bodily fluid that transports nutrients and oxygen in our body, and makes up 7% of our weight. The red blood cells carry oxygen through the body, the white blood cells defend the immune system against diseases, viruses, and other harmful elements, and the platelets prevent blood loss through clotting. Hemoglobin is what makes blood red, and there are 30 recognized blood types in humans. The O blood type is the most common, comprising 37.4% of the U.S. population. People with O blood are “universal donors” because their blood doesn’t have antigens. Their blood type is compatible with any receiver. However, they can only receive blood from fellow O blood types. The AB- blood type is the rarest, making up only 0.6% of the U.S. population. The AB blood type is the “universal receiver” since it has both A and B antigens. Other blood types are usually compatible with them. Transfusi