Africa´s geography, it´s surrounded by water, and has rivers that communicate all the continent, this helped migration, also the camels in the dessert were able to carry heavy loads and walk up to 30 miles a day. When the colonization times arrived, Africa was heavily conquered due to it´s closeness to Europe, and its easy access thru sea, keeping in mind that the salvery times and the trade of slaves was one of the main markets in that time, Africa was the main affected by that.
