<P> A popular Tin Pan Alley song of 1919 asked, concerning the United States troops returning from World War I, "How Ya Gonna Keep' em Down on the Farm (After They've Seen Paree)?". In fact, many did not remain "down on the farm"; there was a great migration of youth from farms to nearby towns and smaller cities . The average distance moved was only 10 miles (16 km). Few went to the cities with over 100,000 people . However, agriculture became increasingly mechanized with widespread use of the tractor, other heavy equipment, and superior techniques disseminated through County Agents, who were employed by state agricultural colleges and funded by the Federal government . </P> <P> In 1919, Woodrow Wilson campaigned for the U.S. to join the new League of Nations, which he had been instrumental in creating, but he rejected the Republican compromise on the issue, and it was impossible to gain a 2 / 3 majority . During a grueling cross-country tour to promote the League, Wilson suffered a series of strokes . He never recovered physically and lost his leadership skills and was unable to negotiate or compromise . The Senate rejected entry into the League . </P> <P> Defeat in the Great War left Germany in a state of turmoil and heavily in debt for war reparations, payments to the victorious Allies . The Allies in turn owed large sums to the US Treasury for war loans . The US effectively orchestrated payment of reparations; under the Dawes Plan, American banks loaned money to Germany to pay the reparations to countries like Britain and France, which in turn paid off their own war debts to the US . In the 1920s, European and American economies reached new levels of industrial production and prosperity . </P> <P> After a long period of agitation, U.S. women were able in 1920 to obtain the necessary votes from a majority of men to obtain the right to vote in all state and federal elections . Women participated in the 1920 Presidential and Congressional elections . </P>

In which of the following categories did the united stated become a world leader after world war i