Europeans bought manufactured goods to Africa in return for slaves.This is important because mercantilism is based on the idea that money is wealth.
They stopped farming and growing crops on one location and started growing and farming crops at another location. This enabled the soil to recuperate and gain the required minerals which makes good soil also fertile
The USA didn't want communism to spread.
Roosevelt wanted to cause inflation to help deal with the Great Depression. The Great Depression caused everyone to lose their money and inflation would have caused them to get more money and the economy would be higher and better.
