Which of the following describes an advantage that secondary sources have over primary sources for historians

The crittenden compromise which option explains the role that this legislation played in the buildup to the civil war? it attempted to resolve the complications introduced by the missouri compromise; this to stave off the civil war. it sought to encourage southern diplomats to take their seats in congress so their voices could be heard in government. it proposed six amendments to the constitution aimed at protecting slavery; however, its passage was blocked by congress. it attempted to establish stipulations that made secession from the united states constitutionally legal.

Why is james madison significant in regards to the bill of rights?

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.