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]: Protons and neutrons are made of quarks, which are fundamental particles of matter.
[EX A]: A fundamental particle of matter, protons and neutrons are made of these?

[EX Q]: Reproduction in prokaryotic cells is by binary fission, enlargement and division.
[EX A]:
Reproduction in prokaryotic cells is by what process of growth, enlargement and division?