instruction:
Given a scientific question, generate a correct answer to it.
question:
Radon is inert and generally unreactive because it is which kind of gas?
answer:
noble gas

question:
Where are free-living roundworms mainly found?
answer:
freshwater habitats

question:
From observations as simple as blowing up a balloon, it is clear that increasing the amount of gas increases what else?
answer:
the volume