Historically west africa shows a high degree of regional complementarity between question 10 options: 1) islamic and african languages 2) french and british colonies 3) former west africa and east africa 4) peoples in the east and peoples in the west 5) peoples of the tropical forest and peoples of the dry interior

Historically, west Africa shows a high degree of regional complementarity between the peoples of tropical forests and the peoples of the dry interior.West Africa has regions covered by tropical rainforests, running along the coastlines of Guinea Bissau, Sierra Leone, Nigeria, Ghana and ending at the Congo basin, as well as dry interiors partially covered by the Sahara Desert. The Sahara covers part of Mali, Niger and Chad. The occupants of these completely different ecosystems show a high degree of complementarity between both of them.