Question

Why does the rotation of earth require people to establish time zones?

Answer 1

The Earth rotates constantly and is exposed to the sun in different intervals & time periods - Thus, people need to establish a time zone to state when & where the sun rises as well as sets during daytime. 

Answer 2

The Earth rotates constantly and is exposed to the sun in different intervals & time periods - Thus, people need to establish a time zone to state when & where the sun rises as well as sets during daytime.