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.

[EX Q]: Sentence1: Many birds perform elaborate courtship dances. 
Sentence2: Many birds perform dances before they mate.
[EX A]: Many

[EX Q]: Sentence1: threatening behavior by predators causes a porcupine to extend its quills. 
Sentence2: Fishers are one of the few specialized predators on porcupines.
[EX A]: predators

[EX Q]: Sentence1: Firm plastic eyeglasses or goggles are better. 
Sentence2: plastic protects the eyes during experiements.
[EX A]:
plastic