Given a statement, generate a question such that the answer is contained in that statement.

[Q]: large animals that roamed the planet were replaced with mammals after their extinction
[A]: What were large animals replaced with after their extinction?

[Q]: Amphibians are hunters of insects
[A]: Who are hunters of insects?

[Q]: an acid changes the coloration of litmus paper from blue to red
[A]:
What color does acid change the coloration of litmus paper from blue to?