<span>b. Masters were allowed to kill their own slaves, if they had a reason for doing so.
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<span>The population of U.S. cities tripled between 1870 and 1900 because of the advantages perceived to come from living in the city, including modern conveniences, such as indoor plumbing and the telephone, higher salaries, increased job opportunities and greater opportunities for amusement. However, city life in the 1800s also often came with overstressed sewage systems, rapidly spreading disease and squalid living conditions. </span>
<span>The Vietnam War had far-reaching consequences for the United States. It led Congress to replace the military draft with an all-volunteer force and the country to reduce the voting age to 18. It also inspired Congress to attack the "imperial" presidency through the War Powers Act, restricting a president's ability to send American forces into combat without explicit Congressional approval. Meanwhile, hundreds of thousands of Vietnamese refugees have helped restore blighted urban neighborhoods.</span>
Spain spent much of the 1920s under the dictatorship of Miguel Primo de Rivera, and the economic hardships caused by the Great Depression intensified polarization within the Spanish public. Labor unrest was widespread in the early 1930s, and the election of February 16, 1936, brought to power a leftist Popular Front government. Fascist and extreme-right forces responded in July 1936 with an army mutiny and coup attempt that expanded into a civil war.
