Question

Advantages and disadvantages of single time zone

Answer 1

Advantage-it lead to unity in country. Sisadvantage-it lead to confusion in time.

Answer 2

Advantages
by having a single time zone, all the people in the world can work at the same time which will substantially contribute to the unity among different nations.
disadvantages
some people will have certain disturbances in their sleep wake cycle because of the single time zone which makes it practically impossible.