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: a wildfire changes an ecosystem drastically. 
Sentence2: Forest fires change an ecosystem drastically.

Answer: changes


Question: Sentence1: Freckles are an autosomal recessive trait. 
Sentence2: crossing two living things with freckles causes their offspring to have freckles.

Answer:
Freckles