instruction:
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.
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: If the skin is painful, seek medical attention. 
Sentence2: If your skin hurts, your touch receptors will sense differences.
answer:
skin


question:
Sentence1: treating water is used to remove harmful substances before drinking. 
Sentence2: Ordinary tap water can be full of harmful substances like chlorine, pesticides and heavy metals.
answer:

harmful