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: forming coal requires decaying vegetation. 
Sentence2: Forming fossil fuels requires decaying vegetation.
[EX A]: decaying

[EX Q]: Sentence1: drought is when amount of precipitation decreases. 
Sentence2: Drought decreases the availability and abundance of the natural food supply.
[EX A]: drought

[EX Q]: Sentence1: a firecracker converts chemical energy into sound. 
Sentence2: Particularly interesting waves are sound waves .
[EX A]:
sound