Nullification is where a state has a right to disagree with a federal law they think is unconstitutional and not correct, and no longer abide by it. Nullification would have weakened the Union because states would no longer have to agree or act on certain laws, causing obvious conflict within the state and conflict between Congress and the state. The state would no longer be unified and a quarrel between people in the state, the states, and between the state and the Congress would deepen and would most likely lead to war and weaken the Union.
The correct answer is B.
The Neolithic Revolution was characterized by the radical transformation of the human way of life, as societies stopped to be nomadic and started to be sedentary, and there was a transition from a hunter-gathered economy to an economy based on agriculture and raising livestock. Birth rates rose spectacularly and this brought an important population growth.
The civil war improved the economy of the north, but harmed the economy of the south. The south relied heavily on agriculture/ producing cotton on slave worked plantations. The civil war led the slaves to finally be freed thus sending many southern farmers into poverty.
A president can have a impact on reform and progressiveness. It can be done by starting or strengthening programs that improve lives.