What clause in the constitution states that the national
government has supreme law of the land?

Plz i will give use examples from the lessons and your own personal experiences to compose at least one well-developed paragraph on the following: define the term reserved powers, and give an example of a reserved power of government.

Why did einstein write a letter to president roosevelt

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.