Answer:
The 20th century was a time of enormous changes in American life. The beginning of the 21st century seems a suitable time to look back over the past 100 years and see how the United States has developed, for better and worse, during that period of its history.
In the early decades of the 20th century the American people benefited from industrial growth while also experiencing its adverse effects. Cheap labor and assembly-line manufacturing made mass production possible. Railroad networks carried the mass-produced goods, many of them the result of new technologies, around the country. Montgomery Ward, J.C. Penney, and other retailers expanded their operations and laid the foundation for the consumer-driven society that evolved later in the century. Materially, city dwellers' standards of living improved steadily, not only in food, shelter, housing, and other material goods, but also in health care and education. Inexpensive books, magazines, newspapers, and improved public libraries, funded in part through the benevolence of Andrew Carnegie, contributed to their intellectual lives. Sexual fulfillment in marital relationships continued to gain importance, and family life increasingly reflected the ideals of companionship. Silent films and amateur and professional sports helped fill leisure time. The Boy Scouts and Girl Scouts, founded in 1908 and 1910, provided recreational and educational opportunities for children.
Determined to make the most of the nation's abundant natural, human, and financial resources, the government supported industrial growth by enacting protective tariffs, welcoming throngs of immigrants, providing railroad subsidies, maintaining a patent system, and looking the other way when abuses occurred. Advocates of Social Darwinism's "survival of the fittest" principles and believers in the doctrine of laissez-faire encouraged a climate resistant to government intervention on behalf of disadvantaged workers and victims of racial, ethnic, or gender discrimination
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A is the answer explantion
If you look at the years of the states and write down the ones in 1889 and 1900, it gets easier. Three that I got were Wshington, Montana, and South Dakota (I'm sure there are more but those were three).
1. Motion of the planets
2. An ellipse
