Final answer:
Trans-Saharan trade routes, camel transport, and the exchange of commodities such as salt, gold, and copper facilitated trade with cultures across the desert.
Step-by-step explanation:
Trans-Saharan trade routes made it possible to develop trade with cultures across the desert. The introduction of the camel revolutionized desert transport, allowing for the establishment of regular long-distance trading caravans. Trade in the Sahara primarily involved the exchange of commodities such as salt, gold, and copper, which were in high demand in different regions. Additionally, the spread of Islam played a significant role in unifying trade networks and fostering mutual trust and respect among traders.