Answer:
I have a straight back and sharp teeth to cut objects.
What has a thumb and four fingers but is not alive?
I take off my clothes when you put on your clothes. I put on my clothes when you take off your clothes
I am a small paradise surrounded by dryness and heat.
I have no weight but I could destroy a mansion. What am I?
It has no top or bottom, but it can hold flesh, bones, and blood all at the same time.