How did time zones first come about?

answer:

system developed in 1869 to create consistency in railroad schedules. The earth's surface was divided into 24 time zones, one for each hour of the day.  Before time zones were established, each community set its own time, based mainly on the movement of the sun.

Explanation:

b.provides a written record of the transaction

the first forms of writing came from them in the form of pictographs around 3100 bc.