Answer:
They have not flesh, nor feathers, nor scales, nor bone. Yet they have fingers and thumbs of their own.
You throw away the outside, eat the inside, then throw away the inside. What is it?
The higher I climb, the hotter I engage. I cannot escape from my crystal cage.
One by one we fall from heaven down into the depths of past, And our world is ever upturned so that yet some time we’ll last.
I'm light as a feather, yet the strongest man can't hold me for more than 5 minutes.
You use it between your head and your toes, the more it works the thinner it grows.