A
B
AB
O
unless you're asking for specifics, like O+ and such, but I think you just wanted the main four, so there you go. hope this helps, but I may be wrong ^^
It could be said that the astronomer who placed the sun in the center of the solar system was Copernicus.
He developed the model of the universe that placed the Sun in the center rather than the Earth. It was considered the Copernican Revolution because of its contribution to science and the change of paradigm.
A fertilized egg splitting into two embryoa
