Final answer:
The similarity lies in the relay-like system of trade, where goods were exchanged multiple times between different merchants throughout the journey until they reached their final destination.
Step-by-step explanation:
One similarity between the commercial interactions in the regions mentioned in the passage and commercial interactions along the overland Silk Roads in the period circa 1200-1450 is the method of changing hands of goods multiple times during the journey. As goods traveled along the Silk Roads, they were exchanged between merchants who each traveled only part of the route, often increasing in price the farther they were from their origin.
This is akin to the relay-like system of trade found along the interconnected routes of the maritime networks and oasis towns mentioned, where products were exchanged at various points, involving a series of transactions before reaching their final destination.