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.
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Question: Sentence1: hearing is used for sensing sound by animals. 
Sentence2: functioning ears are used for sensing sound by animals.

Answer: animals


Question: Sentence1: Most water comes from precipitation. 
Sentence2: aquatic animals require precipitation to survive.

Answer: precipitation


Question: Sentence1: faulting of rock in Earth 's crust causes earthquakes. 
Sentence2: Faulting of rock in Earth 's crust can shatter glass windows for miles.

Answer:
Earth