Which of theses paintings should be considered a secondary source

What was the plight and fight of the following groups? labor farmers native americans african americans women immigrants ~ ap u.s. history (period 6: 1865-1898)

What was a northern objection to the kansas-nebraska act?

23. how does specialization among nations encourage interdependence? nations work together to share labor and resources to produce vital goods. nations sign treaties prohibiting taxes on imports. nations produce specific goods and then trade to obtain things they need. nations that are more developed agree to fund development in nations with limited industry.