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: Plants that shed their leaves seasonally each year are called deciduous plants. 
Sentence2: vines shed their leaves seasonally each year.

Answer: each


Question: Sentence1: Some parasites kill their host, but most do not. 
Sentence2: most tapeworms do not kill their hosts.

Answer:
do