Answer: They led to larger urban cores that used professional armies to increase their territory and enslave people.
Explanation:
Trade routes to West Africa before European colonization was led by Muslim traders who came and converted people to Islam whilst trading.
This trade created large urban areas that grew so rich from trade that they were able to command and maintain larger armies which they used to increase their territories and conquer neighbouring lands and enslave their people. This was how the Songhai and Mali empires became so powerful.
