Answer:
By Moon or by Sun, I shall be found. Yet, if there's no light around, I am undone. What am I?
Use me if you really want to see inside someone
What has a head and a tail, but no body or legs?
What is light as a feather but even the strongest man cannot hold it for more than a few minutes?
I have no voice but I can teach you all there is to know. I have spines and hinges but I am not a door. Once I’ve told you all I cannot tell you more.
What made Cyclops quit teaching?