What contributed the most to human migration more than ten thousand years ago?

sturdy boats were invented.
another ice age occurred.
a major volcano erupted in africa.
a severe drought occurred.

Supporters of using the atomic bomb at the end of world war ii believed that a japan might win the war if the bomb was not used. b americans were tired of war and the us should end it quickly. c russia was developing a bomb and the us needed to use it first. d japan was developing a bomb and the us needed to use it first.

N1947, the united nations create a country

Which concept is plato expressing in the excerpt below? when men have both done and suffered tyranny, and have had experience of both . . they think that they had better agree among themselves to have neither. . —plato, the republic: book ii