Answer:
Long and think, red within, with a nail at the end.
What is the thing which, once poured out, cannot be gathered again?
What can be swallowed, but can swallow you?
In marble halls as white as milk, lined with a skin as soft as silk. Within a fountain crystal-clear. A golden apple doth appear. No doors there are to this stronghold, yet thieves break in and steal the gold.
I have one, you have one. If you remove the first letter, a bit remains. If you remove the second, bit still remains. If you remove the third, it still remains.
If a rooster lays an egg on the exact peak of a barn, which side does it fall?