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: Extinct animals include the dodo, the Tasmanian wolf, the great auk and the passenger pigeon. 
Sentence2: The Tasmanian wolf species was unable to produce offspring.

wolf