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: Insects spread disease and destroy crops. 
Sentence2: Crops are plants that are grown for food or other uses.

Answer: crops


Question: Sentence1: chemical splashing can cause harm to humans. 
Sentence2: chemical splashing can cause harm to animals.

Answer: cause


Question: Sentence1: Acid rain is precipitation which pH is 5.7 or lower. 
Sentence2: gases from burning coal causes precipitation which pH is 5.7 or lower.

Answer:
5