Answer:
I am the noise Santa's reindeers make
I have 24 keys but cannot open any locks. Sometimes loud, sometimes soft. What am I?
I sleep when you are awake, I am awake when you fall asleep. I can fly but no feathers to aid my flight. What am I?
What can travel all around the world without leaving its corner?
You throw away my outside, you cook my inside. Then you eat my outside and you throw away my inside. What am I?
No matter how little or how much you use me, you change me every month.