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: cold fronts cause thunderstorms as they pass by. 
Sentence2: Thunderstorms create havoc.

Answer: thunderstorms


Question: Sentence1: if humans disturb animals in a location then those animals will move to a different location. 
Sentence2: The human being is self-aware.

Answer: humans


Question: Sentence1: fire converts chemical energy into light and heat energy. 
Sentence2: If fuel burns, chemical energy is converted into thermal energy.

Answer:
chemical