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: Earthquakes are natural disasters. 
Sentence2: earthquakes can cause animals to leave an environment.

Answer: Earthquakes


Question: Sentence1: moss causes chemical weathering. 
Sentence2: Sphagnum moss mixed with peat moss.

Answer: moss


Question: Sentence1: if an object is kicked then force is exerted on that object. 
Sentence2: If an object is at rest, a force is needed to make it move.

Answer:
force