explain how poetry

My platonic wife is having a really rough day with academia, and my roommate is taking her oral exam as I write this, so this one is for them. It packs a punch.

You must prepare your bosom for his knife,
said Portia to Antonio in which
of Shakespeare's Comedies? Who killed his wife,
insane with jealousy? And which Scots witch
knew Something wicked this way comes? Who said
Is this a dagger which I see? Which Tragedy?
Whose blade was drawn which led to Tybalt's death?
To whom did dying Caesar say Et tu? And why?
Something is rotten in the state of Denmark - do you
know what this means? Explain how poetry
pursues the human like the smitten moon
above the weeping, laughing earth; how we
make prayers of it. Nothing will come of nothing:
speak again. Said by which King? You may begin.

—Carol Ann Duffy (b. 1955), "Mrs Schofield's GCSE" from The Bees, 2011. This whole collection is great; I bought it because it's called The Bees and because I had read like two Carol Ann Duffy poems and liked them in the past, but now I totally love her. Plus, you kind of have to love a sonnet that is this committed to slant and internal rhymes.