Blood Types: ABO System, Red Blood Cell Antigens & Blood Groups

Type O Blood: O and O- Blood Types - Bloodworks Northwest

In the ABO system, blood group O is characterised by

What blood types are and what they mean for you

9 Rarest Blood Types in the World - Rarest.org

Blood types

Why Some People Believe That This Blood Type Means You Have Alien DNA

ITSN presents: 'THE RH - FACTOR' 11.20 / Blood Type (or Blood Groups: A, B, AB, O, Rh)

How Does the Rh Factor Affect Pregnancies? | Britannica