Which invention during the 19th and early 20th century do you think had the greatest impact on the daily life of americans? why?

Ineed with this unit test 1. japan became a peaceful democratic nation relatively quickly after the end of world war 11 which step is not part of it post-war transformation -adopting a new constitution -disarming most of the military -giving women rights to vote -giving the emperor more political power 2. why did mao start the cultural revolution? -he thought government officials had promoted a very narrow view of communism -he wanted to speed up change and eliminate western, capitalist influence-he wanted to speed up the economy by promoting capitalism -he wanted to restore traditional chinese culture 3. what launched the korean war? -general macarthur led an invasion of north korea -north koreans, with stalin's approval, invaded south korea -south koreans tried to capture the government in p'yongyang-chairman mao urged the south koreans to invade north korea