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

[EX Q]: You see a faster reaction rate when the concentration of reactants is higher.
[EX A]: What kind of reaction do you see when the concentration of reactants is higher?

[EX Q]: Most hormones are produced by the endocrine system.
[EX A]: Most hormones are produced by which human organ system?

[EX Q]: Friction force is caused by microscopic bumps, lumps, and imperfections colliding.
[EX A]:
What force is caused by microscopic bumps, lumps, and imperfections colliding?