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: if an animal lives under ground then that animal will be protected from a wild fire. 
Sentence2: An animal living underground will be protected from an elemental part of the ecosystem.

ground