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

Q: Simple kind of diffusion do small hydrophobic molecules squeeze through lipid molecules.

A: What kind of diffusion do small hydrophobic molecules squeeze through lipid molecules?
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Q: Zero is the net force acting on an object when two equal forces are applied from opposite directions.

A: What is the net force acting on an object when two equal forces are applied from opposite directions?
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Q: The specialized study of the motion of objects that are atomic/subatomic in size is called quantum mechanics.

A:
The specialized study of the motion of objects that are atomic/subatomic in size is called what?
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