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

[EX Q]: Pangaea began breaking apart 250 million years ago.
[EX A]: How many millions of years ago did pangaea begin breaking apart?

[EX Q]: Water contains 3 atoms.
[EX A]: How many atoms does water contain?

[EX Q]: Chemical reactions follow the laws of thermodynamics.
[EX A]:
Chemical reactions follow which laws?