Answer: 1) The Great Chain of Being refers to the idea that God set out an order for all in the universe, similar to the feudal system in ways. The monarch was believed to have been chosen by God directly, and all below the monarch were ordered to follow the ideas presented by them completely; to go against the monarch was seen as a sin.
2) In Act 2 of Macbeth, Macbeth kills Duncan — the king — as he sleeps. This disrupts the Great Chain of Being as it goes against what was believed to be the will of God and the order chosen by the higher power. In Act 3, Macbeth is believed to be punished for his crimes through hallucinations, which could be seen to a superstitious audience as the consequence for breaking the Chain.