Answer:
A box without hinges, lock or key, yet golden treasure lies within.
I am always in front of you, but you will never see me. What am I?
I tremble at each breath of air, and yet can heaviest burdens bear.
What can you share and still have all for yourself?
It can cause deflation of tires when dropped from the rear of spy cars.
What is so fragile that saying its name breaks it?