SciShow Explains Why We Have Different Blood Types

For the latest round of “Quick Questions” by SciShow, Michael Aranda answers the user-submitted query “What Are Blood Types,” taking on the roles that antigens and antibodies play in determining our own types, and how these facts impact blood transfusions.

Our different blood types stem from the fact that we all have immune systems. And while they work equally well, they’re not all the same.