Lots of expensive goods were made along the silk road, and with that they would make more money to more people. The silk road was full of different sellers from different places. That's how different materials were spread to different places.
The cost of transport in ancient times was so great that only expensive ones were taken, the rest by sea.
by carts
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mostly caravans, that carried silk, gold, spices, and supplies[for the travelers].
silk spices precious metals rare pricey stuff
They were expensive to bring back. The overland Silk Road was dangerous and long. It took moths to travel. Many times the travelers were robbed or ships were lost in storms. The cost of the goods was added to the price when they were sold.
No farm animals. Mules, camels, carts., yaks, men, horses, donkeys.
The various items that were traded on Ancient China's Silk Road were high priced goods such as silk, spices, tea, and porcelain. Expensive goods were only taken because merchants had to pay taxes to many kingdoms as they moved the goods East and West.
Goods are transported on the Silk Road usaully by foot. Along the way people will use camels, horses, and yaks to get safely across.
The reason they were on the Silk Road was because they had items they wanted to sell in Europe and that made them of value. They also had to carry money with them and had animals so for any bandit they were a good source of income.
They risked their lives to get silk,pepper,rugs,etc. to sell them at their home and get a lot more money and profit for them.
The route they usually used was the Silk Road which was a trip through mostly Arab nations. On the Silk Road there were people who basically made you pay to use the road. It was expensive, long, and just too much to do.