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: Scientists still know relatively little about Archaea. 
Sentence2: scientists still know relatively little about non-bacterial prokaryotes.
Example Output: Scientists

Example Input: Sentence1: All sharks are predators. 
Sentence2: hiding can be used for avoiding sharks.
Example Output: sharks

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