Children's questions - a request

[user1483976270]

Hi everyone
I have a request - I'm writing a book (working title 'Do Ostriches Have Willies? - A guide to answering your child's incessant questions) and was hoping the Mumsnet hive mind would be able to provide some great examples of questions your kids have asked...
I'm looking for all kinds of questions: Science ones which have left you stumped; Moral ones which have either delighted or worried you; Ones where you're worried whether the 'true' answer is age appropriate; Funny ones; Deep ones; Ones you can't even find answers to via Google.

Current examples: Why is the sky blue?; Why do some dogs have floppy ears?; Why are there antelopes? How do magnets work? Why is fire hot? Do fish drink water? How do you know who to marry if you haven't met everyone in the world? Why don't we feel the Earth spinning? If God is real, who made God?

And what do you think potential buyers of this type of book would especially like to see in it? It's morphing all the time from my original premise, so all thoughts welcome.

Cheers all!