“...were taught taught modern farming techniques by Westerners.”
Yes, that is the solution. Sadly, the 54 countries in Africa had seven thousand years to learn farming techniques and are still struggling. China discovered glass windows in 1910 and toilet paper in 1970. Thus, China and Africa have a lot of catching up to do.
China discovered glass windows in 1910 and toilet paper in 1970.
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For one, China invented TP centuries ago.
http://factsanddetails.com/china/cat2/4sub7/item30.html