1.Why did the U.S.avoid involvement in WWII until December 1

1.Why did the U.S.avoid involvement in WWII until December 1941?Why was the Pearl Harbor attack such a shock to the U.S.2.Why was the invention of penicillin so important in the context of WWII?What were some other advances in medicine that were important during the war?3.How were women affected by WWII?Do you think the war advanced the rights of women?4.During WWII,the American armed forces were still segregated by race.Why do you think this issue became increasingly important during this era,leading to the desegregation of the Armed Forces a few years after the war?

1,America is pursuing isolationism policy. The attack on Pearl Harbor among U.S. suffer casualties is very heavy,Isolationism challenged. 2.Because penicillin was put into use greatly reduces the battlefield soldier's wound infection.Many soldiers to survive, reduce the loss of the war.For the final accumulated a lot of big counter-offensive effectives. Morphine, used by massive tranquilizer, 3,The front man war, women assume a considerable part of social work.To contribute to the society is more and more big, their position in society correspondingly improved. Yes, I do. 4,War in great quantities in American blacks enlistment,For American win wars made contributions.Black power and consciousness rapid growth.Should or something like that.