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: air pollution can cause the pH of soil to decrease. 
Sentence2: Acidity is measured with a pH meter or with pH paper strips.
[EX A]: pH

[EX Q]: Sentence1: a flashlight converts chemical energy into light energy. 
Sentence2: Only as long as there are batteries in the flashlight, the flashlight will function.
[EX A]: flashlight

[EX Q]: Sentence1: microscope is used to see small things by biologists by making them appear bigger. 
Sentence2: Biologists use microscopes to study things that are too small to be seen with the unaided eye.
[EX A]:
biologists