Answer:
Three lives have I. Gentle enough to soothe the skin. Light enough to caress the sky. Hard enough to crack rocks.
What does everyone know how to open but not how to close?
What goes up but never comes down?
Upon me you can tread, though softly under cover. And I will take you places, that you have yet to discover. I'm high, and I'm low, though flat in the middle. And though a joy to the children, adults think of me little.
Dies half its life. Lives the rest. Dances without music. Breathes without breath.
What is so fragile that saying its name breaks it?
Difficult
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?