What reasons does Alexander give to explain why Africans were deemed the ideal slaves?

Alexander attributes the perception of Africans as ideal slaves to factors such as physical traits, geographic location, cultural differences, and historical context. He suggests that Europeans viewed Africans as suitable for slavery due to their physical strength, skin color, geographical proximity to trade routes, cultural practices that were unfamiliar and therefore deemed inferior or barbaric, as well as the historical precedent of slavery in African societies.