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: Chemical weathering causes chemical changes in the minerals of a rock. 
Sentence2: moss causes chemical changes in the minerals of a rock.
A: 
changes