Answer:
I am the key that is the hardest to turn
Fashions change, but what can a person wear that is never out of style?
I'm blue at day and black at night. I do contain some creatures born and died. What am I?
I'm orange when long I'm white when short. What am I?
What is so fragile that saying its name breaks it?
Who makes it, has no need of it. Who buys it, has no use for it. Who uses it, can't see it. What is it?