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: a warm front causes cloudy and rainy weather. 
Sentence2: Stratus clouds are associated with a warm front.

Answer: front


Question: Sentence1: Methane gas is a produced by rotting compost, trash, and human waste. 
Sentence2: Methane gas can be produced by Slime molds.

Answer: Methane


Question: Sentence1: an earthquake causes the ground to shake. 
Sentence2: when an earthquake causes the ground to shake, this shaking can damage buildings.

Answer:
causes