Final answer:
The Sahara was vital to the prosperity of medieval West African kingdoms due to its facilitation of trade routes, the presence of oases as important trade hubs, and the cultural isolation and development it fostered within the region.
Step-by-step explanation:
During the medieval period, the Sahara played a vital role in the prosperity of West African kingdoms despite its hostile environment. One key reason is that the Sahara facilitated trade routes connecting West Africa to North Africa and beyond, allowing for the exchange of valuable commodities like salt. Salt, which was scarce in the inland regions south of the Sahara, was mined in the desert and transported across it via caravans to West African villages and beyond. In addition to salt, gold was another prized trade good that passed through the Sahara, contributing to the wealth of these kingdoms.
The Sahara's oases were also crucial hubs for trade routes in West Africa. The oases, although limited in number compared to the vastness of the desert, were important stops where caravans could restock and connect with other trade routes. West African kingdoms competed for control over these market centers and the movement of goods, further enhancing their prosperity.
Lastly, although the Sahara's harsh environment discouraged large-scale human settlements, it fostered cultural isolation and development within the region. West African kingdoms were able to develop distinct cultural practices and social structures that contributed to their civilizations' prosperity.