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.

[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.
[A]: seismometer


[Q]: Sentence1: a solution is formed by one substance being dissolved in another substance. 
Sentence2: A solution is formed when limestone is dissolved in ocean water.
[A]: formed


[Q]: Sentence1: animals require water for survival. 
Sentence2: Water is the key to life for animals.
[A]:
animals