Answer:
What is lengthened by being cut at both ends?
What does everyone know how to open but not how to close?
Always wax, yet always wane: I melt, succumbed to the flame. Lighting darkness, with fate unblest, I soon devolve to shapeless mess.
When the horse strokes the cat, the wood begins to sing.
Black we are and much admired. Many seek us if they are tired. We tire the horse, and comfort man, and turn White when we've fulfilled your plan.
I stay where I am when I go off. What am I?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?