The Missouri compromise of 1820 provided that

was passed by congress in 1820 to the large increase in U.S. territory as the result of the Louisiana Purchase. It provided that for every new free state that was added to the union, a slave state should be added. In 1803, president Jefferson made the Louisiana Purchase.

Explanation:

the answer to this question is the third option. hope this

answer: the time zones used to be whatever the local authority wanted them to be. one town might have 6am whenever the sun came up and another town had 6am 10 minutes later.  

the trains had a hard time when their orders said to be at a certain point at 6am.  

6am, but who's 6am.  

the railroads got together and set the time zones more or less along the longitude lines across the country.

explanation: