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: skin is used for protecting the body from harmful substances. 
Sentence2: Acids are harmful to tissue.

Answer: harmful


Question: Sentence1: Polyps usually reproduce asexually. 
Sentence2: Polyps usually reproduce several different ways.

Answer: Polyps


Question: Sentence1: After urination, dry the end of the penis and replace the foreskin. 
Sentence2: liquid waste comes out the end of the penis.

Answer:
end