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

[EX Q]: Zinc is active transition metal kind of metal.
[EX A]: Zinc is what kind of metal.?

[EX Q]: Cancer occurs most often in adults over fifty age.
[EX A]: Cancer occurs most often in adults over what age?

[EX Q]: Frogs and toads eating flies event is the best example of competition between species in a pond environment.
[EX A]:
Which event is the best example of competition between species in a pond environment?