Answer:
The source of income the African countries depended on for their prosperity was Trade
Step-by-step explanation:
All depended on salt trade as their source of wealth but
this also allowed them to become vulnerable to foreign
manipulation and invasion with those they traded
with. All became mostly Islamic in religion and trade
with Arabs affected the development of these African
kingdoms economically (trade of salt was a source of
wealth) and politically (as many kingdoms fell to
invasions by them eventually).