Which geographic factor contributed to the formation of independent city-states in ancient greece?

Nationalism led to major conflicts following world war i, especially when:

The rise of advertising in the 1920s. i am good with seeing how advertisements shape the roaring twenties and how it developed a new way of life through modern days. but i am not sure what the details of advertising in the 1920s were. if possible can you send me links (preferrably credential links) to sources that maybe show like the first company to start advertising through the radio, how advertising benefits (statistics graphs), etc.

Which of the following could be seen as a weakness of a two-party system? a. the two-party system limits voters' options in electing officials. b. the two-party system limits debate on issues. c. the two-party system limits the range of solutions that will be considered. d. all of these are weaknesses