Why are there different blood types?: Quick Facts

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The Information Architects of Encyclopaedia Britannica

Last updated

Oct. 26, 2026

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Cluster of human red blood cells with their characteristic disc shape, shown alongside yellow connective tissue fibers under x4000 magnification.

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heredity blood group red blood cell Rh blood group system ABO blood group system antigen genetics Lamarckism DNA RNA gene Testcross chimera chromosome heritability Dombrock blood group system