instruction:
Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
question:
Carbon 14 isotope of carbon is typically used to date ancient items.
answer:
What isotope of carbon is typically used to date ancient items?


question:
In science, something that always applies under the same conditions is called a scientific law.
answer:
In science, what do you call something that always applies under the same conditions?


question:
The liquid in a thermometer expands or contracts to respond to heat or cold.
answer:
How does the liquid in a thermometer respond to heat or cold?