Definition: 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.
Input: Sentence1: Mutations may change the structure of a chromosome or just change a single nucleotide. 
Sentence2: Mutagenic chemicals may change the structure of a nucleotide.

structure