What are sources or starting places of many ideas in the constitution?

Why did some states believe they had the power to overturn federal laws?

Which of these works from the italian renaissance exhibits contrapposto?

How are the republican and democratic presidential candidates chosen? a. they are nominated by their state governments. b. each is nominated by his or her respective party. c. each is chosen by the governor of his or her home state. d. they are chosen by the house of representatives.