Developed countries are facing challenges because their populations are aging due to decreased death rates. losing a sense of economic stability. competing for limited natural resources.

Andreus vesalius is known for being the first scientist to provide detailed and accurate

What was the significance of john hancock's signature on the declaration of independence?

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.