What is the concept of genetic drift?

What event brought the us into wwii? what conflicts happened after the us entered the war? i know the first part of this question, i need with the second part.

Business people who received land grants to recruit new settlers to the area were known by what term

What event started the space race and made americans feel their security was threatened a.) alan shepard's suborbital flight. b.) the launch of sputnik c.) the launch of explorer d.) the cuban missle crisis