The main difference in blood types is related to the presence of protein in each individual type, however, RH negative blood type makes for an interesting exception, as this type does not have proteins.
Popular in internet media culture, there are several theories about the reason behind such protein deficiency and one theory suggests origins from another world.
In other words, people with such a blood type, which constitute about 15% of the human population might be from a different planet.
Theories like this go far and beyond in their explanations but one thing is for certain: people with this blood type have some unique characteristics.
First off, there is the matter of blood donations and this blood type can help any other blood type.
They are compatible throughout the blood scale, with everybody. However, unfortunately for them, they are very limited in their compatibility for receiving blood, as only their own type can help.
Geographically, even though they represent a solid percentage of the human population, they are mostly situated in the north of Europe.