Answer:
What's always coming, but never arrives?
What shoes should you wear when your basement is flooded?
How can you throw a ball as hard as you can, to only have it come back to you, even if it doesn’t bounce off anything?
What is used by man, tossed by trees, everywhere but unseen?
It goes up and down the stairs without moving.
I am a cave full of bones and the house of a worm.
Easy
Animal
Difficult
Food
Funny
Kids
Logic
What am I?