Well, back in the 19th century people had to grow food in order to eat. With the land being a dry and open land of desert and if you didn't know desert land is dry, plants need moist and humid lands to grow. The people of Africa are effected by this because it makes the incapable to produce crops. Even today land in Africa makes them unable to produce crops but in today's society there are shops and transported goods to Africa.
I hope this helps :) sorry it is a hour to late!
