The united states joined world war 2 after:

Although the WW2 began with Nazi Germany's attack on Poland in September 1939, the United States did not enter the war until after the Japanese bombed the American fleet in Pearl Harbor, Hawaii, on December 7, 1941

Hope this helps :D

answer; genetics;

the following men who did not in the unification of italy were.

a) giuseppe mazzini

c) alexander ll

the other two men were camilo cavour and giuseppe garibaldi they the unification of italy by yielding territories in the italian unification. in 1861 italy was declared a united-nation state under the sardinian king victor immanuel ll.