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.

Example Input: Sentence1: Producers make food from inorganic molecules. 
Sentence2: Decomposition is the breakdown of organic molecules into inorganic molecules.
Example Output: inorganic

Example Input: Sentence1: Scyphozoans are the next group of Cnidarians, and they are the familiar jellyfish. 
Sentence2: Scyphozoans are aquatic organisms.
Example Output: Scyphozoans

Example 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.
Example Output:
animal