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.

Q: Sentence1: Mating is generally preceded by courtship. 
Sentence2: Mating is generally similar across species.

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

A: predators
****
Q: Sentence1: Prairie dogs live in underground burrows. 
Sentence2: Prairie dogs are protected from a wild fire.

A:
Prairie
****