Answer:
What has a single eye but cannot see?
Take one out and scratch my head, I am now black but once was red.
What goes in, but never through? I've got some and so do you. We might lend one, or even two, but only if our trust is true.
What has roots as nobody sees, is taller than trees. Up, up it goes, and yet never grows?
The higher I climb, the hotter I engage. I cannot escape from my crystal cage.
Often cooked as fillet, this meat comes from an animal that swims underwater.