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

Answer: fumes


Question: Sentence1: healing requires rest. 
Sentence2: Healing and cell regeneration follows.

Answer: healing


Question: Sentence1: Bird A bird is an animal with feathers. 
Sentence2: Endothermic tetrapod vertebrates is an animal with feathers.

Answer:
animal