What are sources of authority?

Which of the following items would serve as a primary source for a historian studiying the american civil war

Why do you think kush in nubia is not as well-known as egypt? ( me with my exit ticket)

How does the principle of federalism affect the u.s. government? a. it guarantees that the united states will always be a representative democracy b. it ensures that the state governments have greater authority that the federal government c. it creates both separate and overlapping powers for the federal and state governments d.it divides the federal and state governments into three branches