Answer:
What word looks the same upside down and backwards?
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 count time, but have no end. Tick tick, but I am not a clock. What am I?
No matter how little or how much you use me, you change me every month.
White fat and fluffy, May even look like a puppy. Seems heavy but is light, Floats about without a worry, But if it turns dark you have to hurry!
People take me on walks and I run and have fun. What am I?