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: a switch is used to start the flow of current in an electrical circuit. 
Sentence2: lights are on when there is flow of current in an electrical circuit.

Answer: circuit


Question: Sentence1: Antigens are proteins foreign to the body. 
Sentence2: antigens are proteins.

Answer: proteins


Question: Sentence1: eating food that contains pesticides can have a negative impact on humans. 
Sentence2: Pesticides are chemicals that kill pests.

Answer:
pesticides