Answer:
Moral corruption is evident throughout Hamlet. The statement "Something is rotten in the state of Denmark," made by Marcellus in act I scene IV, sums up the moral corruption in the play.
You may have used these other instances of moral corruption in your answer:
Claudius eyeing his brother's wife, Queen Gertrude
Claudius murdering his brother
Claudius marrying his brother's wife
Claudius and Gertrude attempting to convince Hamlet to move on from his father's death and accept his stepfather
Polonius' treatment of Ophelia and his willingness to do the bidding of Claudius
Prince Hamlet plotting to kill his uncle Claudius
Prince Hamlet abusing his mother and calling her promiscuous
Hamlet killing Polonius instead of Claudius
Claudius ordering the king of England to put his nephew, Hamlet, to death
Claudius poisoning Laertes's sword before his duel with Hamlet
Hamlet stabbing Claudius
the death of all the morally corrupt characters of the play (Hamlet, Polonius, Laertes, Claudius, Gertrude, and even Rosencrantz and Guildenstern), which may mean that corruption will lead to death
You may also have used quotes from the play similar to the one below, in which Hamlet laments his mother's sudden marriage to his uncle:
O God! a beast that wants discourse of reason,
Would have mourn'd longer—married with my uncle,
My father's brother...
Step-by-step explanation: