Which group in the 13 colonies was against slavery? why?

The ideas of led to the founding of the democratic party.

Who was marshall mcluhan and what did he have to do with communication theory?

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.