A historian researching Ancient Greece discovers that Greek historians often had few sourses

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.

Supreme court cases can alter history? true or false

Consider the events in alfred wegener's life that led to his development of the continental drift hypothesis. review the items below and determine whether each item is (1) an observation that led alfred wegener to develop his continental drift hypothesis, or (2) evidence wegener gathered to support his proposal.