Answer:
Ultimately, though, the failure of their military campaigns became a key factor leading to the weakening and eventual demise of the Mongol empire in China.
Step-by-step explanation:
There are many things the Mongols did for chinese development like tax farming, foreign taxes, leading to the prosperity of cities along with the reopening of the silk roads, the reunification of china and the reopening of the grand canal and many other ports of trade.