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: Clouds are one form of condensation. 
Sentence2: Clouds are one form of changing from a gas into a liquid by reducing heat energy.

Answer: Clouds


Question: Sentence1: a battery converts chemical energy into electrical energy. 
Sentence2: A battery produces a flow of electrons.

Answer: battery


Question: Sentence1: Urine is the liquid waste product of the body that is excreted by the urinary system. 
Sentence2: The urinary system excretes a substance used in drug testing.

Answer:
excreted