In this task, you need to write a topic word from the given fact. The topic word must have at least one word overlap with the given fact. The topic word often involves adding a new word from a related concept. In your topic word, use at least one word from the given fact. Topic words with two or more words work best.

Q: Fact: Butter is a fat that is a solid at room temperature.

A: butter fat refrigerate.
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Q: Fact: Evolution occurs in response to a change in the environment.

A: Evolution is Evolution is change in the heritable characteristics.
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Q: Fact: Oxygen is just one substance transported by the blood.

A:
Blood.
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