Answer:
The gold/salt trade in Africa made Ghana a powerful empire because they controlled the trade routes and taxed traders. Control of gold and salt trade routes helped Ghana, Mali , and Songhai to become large and powerful.
Philosopher who differentiated two fundamental fields of social studies, history and geography, was "Immanuel Kant".
The philosophy of Immanuel Kant (1724– 1804) can be isolated into two noteworthy branches. His theoretical philosophy, which incorporates power, depends on the normal comprehension of the idea of nature. The second, his political philosophy, involving morals and political logic, depends on the idea of opportunity. Both of these branches have been immensely powerful in the resulting history of rationality.