Why are time zones necessary

A time zone is a region of the Earth that has adopted the same standard time (local time).

-Most adjacent time zones are one hour apart (although a few are 30 minutes).

-They compute their local time as an offset from Greenwich mean time (GMT).

Explanation:

As earth rotates, the different countries or different part of the earth are at daytime and nighttime. Since they have different daylight and nighttime times, we would need time zones.