Answer:
The main goal of the Black Codes was to limit the freedom of African Americans.
The U.S. relies so heavily on oil that if it disappeared then they would probably be dragged down unless they found a better solution.
The U.S needs oil because, it runs cars, and also many other things. It runs boats for trade, airplanes, runs electricity creation plants, and it also creates our roads.
Shi Huangdi was an effective leader because he was the first Chinese emperor that managed to unite the northern China and responsible to the first development of China's great wall.
Not only that, he is also the one that introduces China to the usage of money as a medium of transaction.
An example of data that a historian would use is "pictorial data", since illustrations can provide unparalleled insight into the past--sometimes even more so than books.
