Which of the following is an important factor when evaluating online research sources for a historical research paper

Which statement describes the impact of the 21st amendment?

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.

Which man believed that african americans should actively fight for the rights they deserve, even if they put their lives in danger?