Identify Cause and Effect Why did Europeans explore Africa, Asia, and the Americas beginning in the 1400s

What was the purpose of the federal reserve act

Which piece of legislation granted african americans the right to vote

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.