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: Muscles can only contract. 
Sentence2: Contraction is a type of movement.
[EX A]: contract

[EX Q]: Sentence1: Specialization decreases mortality 12,13 and increases survival. 
Sentence2: evolving different adaptations increases survival.
[EX A]: increases

[EX Q]: Sentence1: Bears are curious animals. 
Sentence2: better senses have a positive impact on a bear's survival.
[EX A]:
Bears