Hich of these pieces of legislation was an important step in limiting slavery?

Ineed asap! ! what is the name of the system in which each branch of the u. s government can limit the actions of the other branches? a. perpetual union b. division of powers c. cooperative federalism d. checks and balances

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.

What is the matter with minds of society these days ?