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: Nephrons are the structural and functional units of the kidneys.

A: Nephrons cause.
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Q: Fact: Most species go through larval stages after hatching.

A: larval stage.
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Q: Fact: Evaporation of sweat uses energy, and the energy comes from body heat.

A:
Evaporation of sweat.
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