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: Crops are plants that are grown for food or other uses. 
Sentence2: insects destroy plants.

Answer: plants


Question: Sentence1: Limestone caves displaying stalactites. 
Sentence2: Limestone caves are formed by depositions.

Answer: Limestone


Question: Sentence1: Some birds are pollinators that co-evolved with plants. 
Sentence2: Hummingbirds are an important groups of bird pollinators.

Answer:
birds