Please help me with as much as possible this is a really hard and important test

Which factor was a major cause of the great depression of the 1930?

Define the term universal male sufferage and give examples of when it affected the revolutions of 1848

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.