By taking constitutional law as a political doctrine, the US constitution establishes that the government is divided in three different branches (executive, legislative and judicial) in order to prevent power abuse from those in the position of authority. This division it's also known as the system of checks and balances, its main function is to keep each of the branches accountable for their decisions.
The answer to Question 7 is Totem Pole and let me see if I can get you the answer to Question 6
While building the Great Wall of China, thousands of peasants died. They were forced to build the wall and were never given the proper care they needed so they ultimately died while trying to construct it.
Because they wanted to improve sailing ships.