Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

[EX Q]: Diffusion is the term for the movement of molecules from an area of high concentration to an area of low concentration.
[EX A]: What is the term for the movement of molecules from an area of high concentration to an area of low concentration?

[EX Q]: Water and humidity is the critical factor for the survival of segmented worms.
[EX A]: What is the critical factor for the survival of segmented worms?

[EX Q]: The low atomic number of beryllium allows it to absorb x-rays.
[EX A]:
What aspect of beryllium allows it to absorb x-rays?