Long Riddles and Answers

Question: I am important at the most dangerous times. I can not be seen, heard, or smelled. If you use me too much you would fatally die. What am I?

Question: You have a cube made of 10 x 10 x 10 smaller cubes, for a total of 1000 smaller cubes. If you take off 1 layer of cubes, how many remain?

Question: I may be of the eye,
in order I am pie,
in my center there is a star,
I keep medics where they are.

What am I?

Question: Swallowing one is fine.
Swallowing two together is fine.
But Swallow them separately and all shall fall.

What are they?

Question: a mans car gets stolen but all the windows are up and the doors are locked there is no holes or breaks in the car how does it get stolen?