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

[Q]: Rubber is an example of a(n) insulators that does not allow electrons to move through them.
[A]: Rubber is an example of what type of substances that do not allow electrons to move through them?


[Q]: Digestion begins in the gastrovascular cavity.
[A]: Where does digestion begin?


[Q]: Craters and rifts become lakes when they fill with water.
[A]:
What do craters and rifts become when the fill with water?