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: Habitat destruction is the primary cause of extinction or threat of extinction for all animals. 
Sentence2: building housing developments may cause extinction.
Example Output: extinction

Example Input: Sentence1: information in an organism 's chromosomes cause genetic traits to be passed down to that organism 's offspring. 
Sentence2: information in Man's chromosomes cause genetic traits to be passed down to offspring.
Example Output: chromosomes

Example Input: Sentence1: Architects build buildings. 
Sentence2: Architects create structures that use energy for heating.
Example Output:
Architects