What is the relationship of interaction to the rise and fall of Ghana Empire, Mali Empire and pre-colonial States?

The relationship of interaction with per-colonial States

Explanation:

Rapidly growing trade brought a lot of wealth and power to West Africa. The rise of the many empires in Africa began with the trading connection. The trade with other region earned the empires like Ghana and Mali prosperity. Ghana Empire became wealthy because of gold smelting. The empires rose to prominence through wealth from trade and maintained strong cavalry. A large army of Ghana helped to secure the borders, controlling minor revolts, and maintaining peace and order in the empire and neighbours. The Mali Empire rises as gold became the centre of the trans-Saharan trade.

the captain of a steam ship naturally chooses the shortest route to his destination. since a sailing ship is usually pushed by winds and currents, its captain must find a route where the wind will probably blow in the right direction. tacking, i.e. using contrary wind to pull (sic) the sails, was always possible but wasted time because of the zigzagging required, and this would significantly delay long voyages. the early european explorers were not only looking for new lands. they also had to discover the pattern of winds and currents that would carry them where they wanted to go. during the age of sail winds and currents determined trade routes and therefore influenced european imperialism and modern political geography. for an outline to the main wind systems see global wind patterns.

pilotage or cabotage, in one sense, is the art of sailing along the coast using known landmarks. navigation, in one sense, is the art of sailing long distances out of sight of land.[1] although the polynesians were able to sail the pacific (with great difficulty) and people regularly sailed north and south across the mediterranean, before the time of columbus nearly all sailing was coastal pilotage

        it is some were in here? ///

the anwser is a) to prevent military conflict