The correct answer to this question is the following.
Many Chinese merchants traveled only as far as Dunhuang on the Silk Road, basically for the following two reasons. 1) During those years, Dunhuang becomes an important hub place for trade in the Silk Road, where people met to commerce all kinds of products. 2) Dunhuang in the middle of some crossing paths. Indeed it was the intersection of the central, north, and south silk routes. That is why Dunhuang represented a strategic place with so many logistic operations in the Taklamakan Desert, in the northwest of China.
The Caddo and Jumano typically hunted for their food, as they did not live in a climate suitable for agriculture.
The Coahuiltecan and Apache on the other hand, preferred to grow crops instead of hunting for animals, as they lived in appropriate agriculture climates.
