Why did independent city-states develop in ancient greece? choose all answers that are correct. a. some of the city-states were isolated because they were islands. b. independent city-states provided protection against attack from other countries. c. the mountains separated groups of people from one another. d. people depended on the many navigable rivers for travel and communication.

What challenges did michelangelo face when he was painting the ceiling of the sistine chapel

Brainles asap!me : -how has religious fundamentalism been used by extremists in the middle east?

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.