her comment reeks of ignorance and insecurity.
lesotho, jamaica, burundi, south sudan, tanzania, ethiopia, nigeria, trinidad & tobago, brazil, congo, rwanda, eritrea and namibia are just some of the black countries whose borders either were drawn up due to natural geographical features or have changed significantly since the colonial era.
borders aren't simply these static, eternally definitive lines on a map, drawn by mustachioed 19th century pink skinned smallpox transmitters. they are constantly changing and evolving.
also, as hard as may be to believe for some people, black people on occasion have hand a hand in determining them too.
don't give these divisive agents attention they crave.
Regardless of any natural geographical features you don't seem to deny that the borders were drawn by Europeans. The border of Cameroon and Nigeria were drawn by the English and the French, despite the fact that mountains are around.