What effect did inflation have on germany after world war 1?

Interest groups are protected by the first amendment guarantees of petition. and what other freedom?

Why was it difficult fpr unions to succeed in the 1800s

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.