Why was an amendment added to the constitution to set presidential term limits?

Why would the rumor of a government contract change the value of this companys stock

The internal combustion engine was an innovation of

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.