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: mountains are formed by earthquakes. 
Sentence2: Mountains are formed by moving plates.

Answer: are


Question: Sentence1: boiling means change from a liquid into a gas by adding heat energy. 
Sentence2: boiling means changing from liquid to a gas by adding joules.

Answer:
boiling