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: Viruses contain DNA but not much else. 
Sentence2: viruses contain encoded information but not much else.

A: Viruses
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Q: Sentence1: plucking a string can cause that string to vibrate. 
Sentence2: plucking a string can cause that string to produce sound.

A:
can
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