Answer:
What is the freedom of birds and the pen of old men?
Hard to catch, easy to hold. Can't be seen, unless it's cold.
What has a single eye but cannot see?
To unravel me you need a simple key, no key that was made by locksmith's hand. But a key that only I will understand.
I tremble at each breath of air, and yet can heaviest burdens bear.
What is so fragile that saying its name breaks it?
Difficult
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?