Are we talking about the rivers?
Answer:
That's where they were able to find the resources they needed for economic growth like minerals such as iron and gold. They didn't settle somewhere else because no other land had the resources they were looking for.
Reformers in the U.S. adopted the idea that students should have access to the same content at similar grade levels.
The point that is considered the starting point of the fall of Tang Dynasty is during Emperor Mu Zong reign, around the year of 821-824. He is known for his high-spending, alcoholics habits and as neglectful emperor.
The correct answer is The fall of the Tang Dynasty began with lack of leadership.