After WWII, the and the emerged as Superpowers. This led to competition that created the . The U. S and Soviet Union

in 1803 the louisiana purchase took place, doubling the size of the country. by 1840 almost 7 million americans had migrated westward in hopes of securing land and being prosperous. the belief that settlers were destined to expand to the west is often referred to as manifest destiny.

explanation:

troy donahue,   i think.