instruction:
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.
question:
Sentence1: Rivers, rainwater, well water and most lakes contain fresh water. 
Sentence2: canyons are formed by rainwater.
answer:
rainwater


question:
Sentence1: keeping food cold is used for keeping food fresh. 
Sentence2: Keeping food cold is used to keep food simple and natural as possible.
answer:
cold


question:
Sentence1: Adolescence is a time of significant mental, emotional, and social changes. 
Sentence2: hormones are to blame for a time of significant mental, emotional, and social changes.
answer:

changes