How did innovations and inventions best benefit both industry and citizens?

What is the purpose of the system of checks and balances

Examine these two paintings that depict famous events from american history. the image on the left, painted in 1940, shows the signing of the u. s. constitution in 1787. the image on the right, painted in 1836, shows the american victory at the battle of yorktown in 1781.which of these paintings should be considered a secondary source?

Which would be good historical evidence when studying manifest destiny?