>>38
It's not really a dilemma, Africa (or any other place in the world for that matter), is not inherently obligated to "give the rest of world anything". Sorghum and millet are traditional crops to Africa, even though they're grown in other parts of the world. Sure, large scale agriculture (or at least large enough to develop a small city) was not really developed (except for maybe the Nok culture), but for all we know, there could have been micro farms no bigger than a tenth of a hectare, enough to satisfy any applicably sized tribe.
Needs are mostly relative, if there's not much of a need to expand, then expansion is likely not to happen.
>>39
What are you on about?