Answer: The Great Wall of China was built as a military defensive line to defend the invasions from some northern nomadic nations. Apart from the function of defense, the wall also boosted the economy, as well as promoted the culture exchange and national integration of different nations at its two sides.
Explanation:
The doctrine that allowed people living in the territories to decide the issue of slavery through their governmental bodies was called "popular sovereignty," since this held that the people were ultimately in charge of whether their state was "slave" or "free".
The war industries could set prices for key war materials such as steel, iron, and rubber.