The main reason why external criticism is so important when it comes to analyzing data is because as the handler of the data yourself, you can quickly develop a bias and "expect" a certain outcome, which might affect your analysis.
Pearl Harbor because Japanese and then war then war
The first one is great lakes
Land, mining, and improved transportation by rail brought settlers to the American West during the Gilded Age. New agricultural machinery allowed farmers to increase crop yields with less labor, but falling prices and rising expenses left them in debt.
