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: Introns are regions that do not code for proteins. 
Sentence2: regions that do not code for proteins are removed by RNA splicing.
Example Output: code

Example Input: Sentence1: Instead, the body is covered with a protective shell of bony armor. 
Sentence2: Most mollusks have protective of bony armor.
Example Output: armor

Example Input: Sentence1: Erosion sculpts the landscape, creating fantastic rock formations. 
Sentence2: Rain causes rock formations and sculpts landscapes.
Example Output:
formations