The answer is "it kept the balance of slave states and free states equal"
The Missouri Compromise is created in order to form a balance between the free states and slave states. In this compromise, it gave Missouri a chance to become a slave state, in turn, Maine would become a free state.
The 13th amendment abolished slavery within the U.S or any place subject to their jurisdiction
Music is created on what stage the culture is in. In the 60's and 70's you never herd a song about the things you hear today