What are some key characteristics that define the 1920s time period so far?

There are many typical characteristic for 20s:  

I WW and some of "reorganization" of the word which caused:

We can simply say that after the I WW began a new order not only in political connections but also in people's lifestyle.

answer: idk

explanation: because i just don't

answer; ///i do believe that the correct answer is (d); ///athens had a small population;