Answer:
There is an ancient invention. Still used in some parts of the world today. That allows people to see through walls.
My teeth are sharp, my back is straight, to cut things up it is my fate.
Look into my face and I'm everybody. Scratch my back and I'm nobody.
What has a bell but isn't a church. Is full of air but is not a balloon?
What stays on the ground but never gets dirty?
What covers its face with its hands, speaks no language, yet most known what it's saying?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?