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: folding an object causes that object to change shape. 
Sentence2: Folding an object causes that object to transform.

Answer: causes


Question: Sentence1: if an object is kicked then force is exerted on that object. 
Sentence2: if an object is kicked then a measurement of newtons is exerted on that object.

Answer: exerted


Question: Sentence1: optical tools are used for observing materials up close. 
Sentence2: Microscopes enable a person to observe a material up close.

Answer:
close