Answer:
I cannot be burned in fire or drowned in water. What am I?
I am an odd number. Take away one letter and I become even. What number am I?
Curtail me thrice I am a youth; behead me once a snake; complete I'm often used in truth when certain steps you'd take.
I climb higher as I get hotter. I can never escape from my crystal cage.
I have six faces but not even one body connected, 21 eyes in total but cannot see. What am I?
It has no top or bottom, but it can hold flesh, bones, and blood all at the same time.