How did the US react to the first world war?
Because Corey buxton said so
World War 2 was the only war with US involvement that didn't involve a large, organized dissent movement. Pearl Harbor was evidence that an 'isolationist' stance was untenable. As knowledge of fascist and Nazi atrocities increased, more and more of the US population saw that US involvement was defendable. See link.
How did the dispersion of global economic activities lead to the US becoming a world power after world war 1?
Not at all, the US joined the war after it began. World War 2 was began by Adolf Hitler, the leader of Germany, because he was unhappy with the fact that Germany lost the first world war. He also strived for global domination and to eradicate the Jews, whom he believed were responsible for the assassination that caused the first world war. The United States only joined the war because Japan attacked them.