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.

[EX Q]: Sentence1: a seismometer is used to measure the strength or magnitude of an earthquake. 
Sentence2: Seismometer Calibration : Instructions on how to calibrate a homemade seismometer.
[EX A]: seismometer

[EX Q]: Sentence1: Batteries are a better source of DC electricity. 
Sentence2: a flashlight requires batteries to produce light.
[EX A]: Batteries

[EX Q]: Sentence1: Most hormones are regulated by feedback mechanisms. 
Sentence2: Hormones help the body manage stress.
[EX A]:
hormones