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: a fire requires oxygen to burn. 
Sentence2: A fire requires something with exactly eight protons to burn.
[EX A]: burn

[EX Q]: Sentence1: Instead, the body is covered with a protective shell of bony armor. 
Sentence2: Most mollusks have protective of bony armor.
[EX A]: armor

[EX Q]: Sentence1: hurricanes convert heat energy into mechanical energy. 
Sentence2: Hurricanes A hurricane is a type of tropical cyclone.
[EX A]:
hurricanes