Final answer:
Trans-Saharan trade and Silk Roads trade both involved the exchange of valuable goods such as spices and precious metals, linking diverse economies and facilitating cultural exchanges.
Step-by-step explanation:
One similarity between trans-Saharan trade and trade on the Silk Roads in Asia is that both involved the exchange of valuable goods such as spices and precious metals. These routes were integral to enabling strong trade relationships and the diffusion of goods over a vast network, connecting markets from China to the Western end of the world, including key commerce centers in Africa, the Middle East, and Europe. The exchange of luxury items and basic commodities along these trade routes facilitated not only economic prosperity but also the spread of cultures, languages, and religions, profoundly impacting the regions involved.