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: Eggs are usually laid in a nest. 
Sentence2: birds have nests.

Answer: nest


Question: Sentence1: Cell death occurs by activation of cell death genes. 
Sentence2: Aging is associated with the activation of certain genes.

Answer: activation


Question: Sentence1: when a hurricane moves over land , that hurricane will decrease in strength. 
Sentence2: Once a hurricane reaches land the source of warm moist air is extinguished and the hurricane dies.

Answer:
land