Which theory of the spread of human beings is supported most by modern evidence apex?

How did presidential reconstruction allow black codes to be passed

The second westward surge reached the: mississippi river, appalachian mountains, oregon territory

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