Federalism is the division of power between states and the federal government.
Federal law preempts state law. This is due to the National Supremacy Clause in Article 6 of the U.S. Constitution.
You said it's free response and all we had to do was answer so here's me doing the bare minimum. Lol.
Many North African nations practice Islam because many Muslims traded in that region, so the North Africans converted to Islam, whereas those in Sub-Saharan African nations were more prone to Christianity because of the trade they did with Europeans.