The first people migrated to America at the end of the last ice age because sea levels decreased from the massive glaciers providing a temporary bridge (Bering Land Bridge) connecting the old world and the new world. Scientists and Anthropologists predict this event occurred after 12,600 BP approximately 20,000 years ago
Explanation:
Over time this answer could change as newer technology and innovations are seen yearly.
It was neutral stance. During the offset of world war 2 the United States stays neutral in order to be part again of another world war but still continue to supply and aid the allied army like weapons and volunteers from the american army. Also the United States were able to supply and lend lease some of its world war 1 vintage ships to Great Britain.