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: Rivers, rainwater, well water and most lakes contain fresh water. 
Sentence2: canyons are formed by rainwater.
[EX A]: rainwater

[EX Q]: Sentence1: Speciation events are thus examples of macroevolution. 
Sentence2: Speciation events occur over geologic time above the level of the species.
[EX A]: Speciation

[EX Q]: Sentence1: All fungi are obligate heterotrophs. 
Sentence2: obligate heterotrophs get organic compounds from dead organisms.
[EX A]:
heterotrophs