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

[Q]: statement: significant physical, emotion, and social changes can be a trying time, question: What types of changes can be a difficult time?
[A]: physical, emotion, and social


[Q]: statement: fish secrete a mucous covering over their exterior to help protect from predators and parasites and reduce friction with the liquid substance they live in., question: What do fish secrete over their exterior to help protect against predators and parasites?
[A]: mucous


[Q]: statement: charting ancestry on a graph is a useful tool for studying inheritance traits., question: What is charting ancestry on a graph useful for studying?
[A]:
inheritance traits