Answer:
Civilizations expand through trade, conflict, and exploration. Usually, all three elements must be present for a civilization to grow and remain stable for a long period of time.
Explanation:
Answer:
Agricultural yields were about 2 tan (a unit of about 110 pounds or 50 kilograms) of grain per mu during the Song dynasty, compared with 1 tan during the early Han and 1.5 tan during the late Tang.
Explanation:
