Given a scientific question, generate a correct answer to it.

Q: The nervous system is characterized by electrical signals that are sent from one area to another. whether those areas are close or very far apart, the signal must travel along this?

A: axon
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Q: What are the ice crystals that form on the ground called?

A: frost
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Q: Teeth in the back of the mouth are used for what?

A:
grinding food
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