How do we decide what is important to learn about the past

By understanding our past, and where we came from, we hope to better understand where we are now and even decide what might happen in the future. The way things are now is a consequence of the things that happened in the past. The way things will be tomorrow will be a consequence of the way things are now. The importance of teaching history.

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:

we need the map to answer the question