In this lesson, you learned about restrictive immigration laws that were passed in the 1920s, and some of the reasons behind them. Compare those laws—and the reasons behind them—with current debates about immigration in the United States.

its many islands, high mountains, and remote peninsulas isolated population centers.

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:

the united states began searching for a way to reduce oil

-agarvated