Answer:
The economy struggled as China became unable to protect its long-distance trade routes.
Step-by-step explanation:
There were many natural calamities that affected China back then, during the Tang Dynasty. Besides that, the Huang Chao Revolution happened. Although the Tang Dynasty did defeat the revolution, this conflict weakened significantly the military power. Which would be felt in the future by the Dynasty. By its end, the Tang Dynasty could not even protect China's own trade-routes.