Generate an overlapping word between the given two sentences. When you find the overlapping words, they don't have to match exactly, e.g., "survival" and "survive" are valid overlapping words. Little words like "the" or "of" don't count! You must generate significant words which are not the stop words.

Q: Sentence1: Echinoderms use pheromones to communicate with each other. 
Sentence2: Echinoderms are known for their round symmetry.

A: Echinoderms
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Q: Sentence1: sharpening an object causes that object to change shape. 
Sentence2: sharpening a knife causes it to change shape.

A: causes
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Q: Sentence1: Sweat wets the skin, and when it evaporates, it cools the body. 
Sentence2: Skin is hot and red, but wet with sweat.

A:
Sweat
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