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: Light is the visible form of electromagnetic energy. 
Sentence2: Electromagnetic energy enters the eye through an opening called the pupil.

Answer: electromagnetic


Question: Sentence1: Cancer is a disease in which cells divide out of control. 
Sentence2: Cancer is a disease in which cells grow and divide rapidly.

Answer: Cancer


Question: Sentence1: Lung cancer is most often caused by exposure to tobacco smoke. 
Sentence2: Tobacco is most commonly smoked in cigarettes.

Answer:
smoke