I wonder....if this is a multiple choice question? If not I believe the monster represents the societal fear of illness and disease.
<span>The following are the lines 16–18 (Act 2, scene 1), in which Macbeth tells Banquo that he and his wife couldn’t entertain the king as they would have liked.
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Being unprepared,
Our will became the servant to defect,
Which else should free have wrought
= these lines are ironic because the wife of Baquo liked to entertain the king but she can't because she is not prepared. Her will to entertain may cause a mistake because she was not prepared what should be carefully done.
Vital could mean something that is important or essential.
For example: the lungs and heart are both vital organs in the human body.
