Which project led to the creation of a system of time zones across America?

America's railroads began using a standard time system involving four time zones, Eastern, Central, Mountain and Pacific

Explanation:

I used the the History Channel website and I got the question right on a test

nuclear weapons are hoaxes. many people believe they are real, though.

a u.s. citizen has to have lived in and been an american citizen for a year or more be for he or she can vote for presidential or country wide elections. they also have to register to vote. if the voting is for state representatives or issues, they have to have lived in that state for one month or more and meet the requirements for country wide elections.