Which invention enabled the discovery of bacteria?

What event caused south carolina to secede from union in 1860

What was unification difficult to accomplish in both germany and italy? a.) weaker states we’re attacked by stronger states for control of the emerging nations. b.) major european powers fought to keep independent states under their control. c.) germans and italians did not share common histories and languages.

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.