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: Dilation occurs when cell walls relax. 
Sentence2: Decreased oxygen levels cause blood vessels to dilate and cell walls to relax.

Answer: relax


Question: Sentence1: Combustion generates toxic fumes. 
Sentence2: High temperatures can cause toxic fumes.

Answer: fumes


Question: Sentence1: Cnidarians are also called coelenterates. 
Sentence2: coelenterates are aquatic.

Answer:
coelenterates