Out of the 5 divisions of humanity that have populated/are populating Africa why, according to Guns, Germs, and Steel, was it the "Blacks" who became widespread instead of the other four groups?
In Chapter 19, Diamond discusses “How Africa Became Black.” He talks mainly about how it was that the “black” Africans took over land that had previously been home to Pygmies and to Khoisan. In keeping with the main thrust of this book, Diamond argues that it was farming that allowed the blacks (also called Bantus) to come to dominate sub-Saharan Africa.
Throughout this book, Diamond argues that farming societies are stronger than hunter-gatherer societies. This is because they can have larger populations and more technology. Diamond says that this is what happened in Africa as well. The Bantu had agriculture where the Pygmies and the Khoisan did not. This allowed the Bantu to be more powerful than the other groups. Therefore, they took over most of sub-Saharan Africa and the other groups only remained in areas that were not really good for agriculture.