instruction:
Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
question:
A skeleton that consists of hard, mineralized structures located within the soft tissue of organisms is called endoskeleton.
answer:
A skeleton that consists of hard, mineralized structures located within the soft tissue of organisms is called what?

question:
The metallic bond is responsible for the properties of metals.
answer:
What is responsible for the properties of metals?

question:
Drinking straw of these is most flexible.
answer:
Which of these is MOST flexible?