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

[EX Q]: Catalyst gets poisoned happens if a molecule forms strong bonds to the catalyst.
[EX A]: What happens if a molecule forms strong bonds to the catalyst?

[EX Q]: Pressure and vibration are examples of physical type of stimuli.
[EX A]: Pressure and vibration are examples of what type of stimuli?

[EX Q]: A tracer is the name for a substance that can be used to follow the pathway of that substance through some structure.
[EX A]:
What is the name for a substance that can be used to follow the pathway of that substance through some structure?