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

[EX Q]: Natural resource type of resource is limited in supply and cannot be replaced except over millions of years.
[EX A]: What type of resource is limited in supply and cannot be replaced except over millions of years?

[EX Q]: The properties of the alkali metals are similar to each other as expected for elements in the same family.
[EX A]: The properties of the alkali metals are similar to each other as expected for elements in the same what?

[EX Q]: When magma reaches the surface through cracks in the earth's crust, a volcanic eruption occurs.
[EX A]:
When magma reaches the surface through cracks in the earth's crust, what occurs?