The Too Hard Puzzle

No apologies, no excuses!

1. Explain the significance of the following set of four words: arrow, carouse, castle, and persuade.
2. Why does the porridge bird lay its egg in the air?
3. Why is the mink excessively tenacious of life?
4. What does the crocodile have for dinner?
5. Whose was it?
6. Why is a raven like a writing desk?
7. Cyril Connolly?
8. There is a man, a certain man, and for the poor you may be sure he will do all he can. Who is this one? This favorite son?
9. The G in Maynard G. Krebs?
10. Mr - Darcy?
11. Chief Inspector - Morse?
12. What's new?
13. Closed on account of death?
14. Punch, Brother, Punch, Punch With Care!
15. Where, please, are the crown jewels hidden?
16. The magic words are...?

I give up, show me the solution.