The Monroe doctrine said that European colonization on American land was an act of aggression. So, of the choices you provided the second one is correct.<span />
Answer: The early 20th century was an era of business expansion and progressive reform in the United States. The progressives, as they called themselves, worked to make American society a better and safer place in which to live. They tried to make big business more responsible through regulations of various kinds. They worked to clean up corrupt city governments, to improve working conditions in factories, and to better living conditions for those who lived in slum areas, a large number of whom were recent immigrants from Southern and Eastern Europe.
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American citizens are well known by their optimism, and it was not an exception during Alexis de Tocquevill’s time. He was a French observer of American life in the 19th century and according to his views on Americans on those days, quote: “they have all a lively faith in the perfectibility of man [...].They all consider society as a body in a state of improvement.” In opposition to the rest of the world, enthusiasm, energy, and confidence in their country’s future characterized American citizens.
Quote: “Most Americans seem to believe that the future can be better and that they are responsible for doing their best to make it that way.”