Final answer:
During Roosevelt's presidency, the U.S. faced dangers such as totalitarianism and Japan's victories, and assumed responsibilities such as aid to anti-totalitarian nations and balancing isolationism.
Step-by-step explanation:
During Franklin D. Roosevelt's presidency, the United States faced several dangers and assumed various responsibilities. One notable danger was the threat of totalitarianism, and the responsibility taken by the U.S. was to provide increased aid to nations fighting against it while maintaining neutrality. Another danger was the risk to American interests in Asia due to Japan's ongoing victories, which led to the U.S. stepping in to support its own interests. Lastly, Roosevelt had to balance the isolationist tendencies of American citizens with the responsibility of aiding the Allies during World War II.