Humans have possible four general blood types: A, B, AB and O; this classification is derived, according to scientists from proteins which are found on the surface of cells which are designed to fight off bacteria and viruses in the human body. The vast majority of humans beings on this planet have these proteins which means they are Rh positive. But a minor group, the Rh Negative lacks these proteins. So how is this crucial difference explained scientifically? And why does it even exist? Throughout the years, several scientific studies have searched for this answer.

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