Answer:
who do you think you know but sometimes you don't
What lies in a tunnel of darkness. That can only attack when pulled back?
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'm a god. I'm a planet. I measure heat.
What has a mouth but can't chew?
They are many and one, they wave and they drum, Used to cover a state, they go with you everywhere.