Which statement correctly describes measuring with a graduated cylinder? A: The liquid in the cylinder usually forms a convex meniscus.
B: Measurement is taken at the bottom of the meniscus.
C: Measurement is taken at the top of the meniscus.
D: The liquid in the cylinder can only be water.

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:

industrial revolution, in modern history, the process of change from an agrarian and handicraft economy to one dominated by industry and machine manufacturing