“Although much remains obscure, and will long remain obscure, ... I am convinced that Natural Selection has been the main but not exclusive means of modification.” MeanLongHas BeensNaturalRemainsConvincedObscureSelectionExclusiveNatural SelectionModification Book:The Annotated Origin: A Facsimile of the First Edition of On the Origin of Species Source: The Annotated Origin: A Facsimile of the First Edition of On the Origin of Species