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: First, the bottle is calibrated with a graduated cylinder. 
Sentence2: calibration is performed with a cylinder.

Answer: calibrated


Question: Sentence1: Batteries are a better source of DC electricity. 
Sentence2: a flashlight requires batteries to produce light.

Answer: Batteries


Question: Sentence1: Air pollution harms the respiratory and circulatory systems. 
Sentence2: Breathing air pollutants can increase the chances of experiencing health problems.

Answer:
Air