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: Babies that are very large or very small at birth are less likely to survive. 
Sentence2: Poor nutrition while in the womb is the major reason why babies are small at birth.
[EX A]: birth

[EX Q]: Sentence1: threatening behavior by predators causes a porcupine to extend its quills. 
Sentence2: Fishers are predators that can eat porcupines.
[EX A]: predators

[EX Q]: Sentence1: Menstruation occurs after the secretion of progesterone stops. 
Sentence2: Menopause occurs when  secretion of progesterone stops.
[EX A]:
progesterone