Answer:
I am the greatest teacher out of them all, but alas in the end I kill my pupils.
Turn us on our backs and open up our stomachs you will be the wisest of men though at start a lummox.
Covered in stone and sun. It's home to many but also none. What is it?
Always wax, yet always wane: I melt, succumbed to the flame. Lighting darkness, with fate unblest, I soon devolve to shapeless mess.
When can someone truthfully tell someone βwell doneβ but think they did a bad job?
What covers its face with its hands, speaks no language, yet most known what it's saying?