In this task, you are given a question and a corresponding answer. Your task is to generate a fact statement that is useful in answering the given question.
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Question: Question: Gills are used by what for breathing water? Answer: marlins.

Answer: gills are used for breathing water by aquatic animals


Question: Question: Many animals that give birth to live young have? Answer: skin.

Answer: live birth means developing inside the mother instead of an egg


Question: Question: Where would rocks be the smoothest? Answer: where water has flowed for years.

Answer:
contact between rocks over long periods of time causes rocks to smooth