Under the truman doctrine, the united states agreed to

Correct  The US agreed to provide financial and military aid to countries fighting a communist takeover.

Explanation/detail:

The Truman Doctrine was first stated by the president to Congress in 1947, saying:  "It must be the policy of the United States to support free people who are resisting attempted subjugation by armed minorities or by outside pressures."  Essentially, the Truman Doctrine pledged American effort elsewhere in the world to check the spread of communist and Soviet influence.  The policy was first put into action in 1948 by providing economic support to Greece and Turkey to stave off communist movement in those countries.

explanation:

japan participated in world war i from 1914 to 1918 in an alliance with entente powers and played an important role in securing the sea lanes in the west pacific and indian oceans against the imperial german navy as the member of the allies.

the federalist party which advocated strong centralization dominated the united states government till 1800. so 1800 election transformed the power from one party to another party for the first time and was thus a turning point in american history. so jefferson called it "revolution of 1800".

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