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: Antigens are proteins foreign to the body. 
Sentence2: antigens are proteins.

Answer: proteins


Question: Sentence1: moss causes chemical weathering. 
Sentence2: Sphagnum moss mixed with peat moss.

Answer: moss


Question: Sentence1: uneven heating of the Earth 's surface cause wind. 
Sentence2: Chinook winds are warm, dry winds.

Answer:
wind