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


[Q]: Sentence1: propulsion is used for flying by a spacecraft. 
Sentence2: When Apollo 12 took off, the spacecraft was hit by lightning.
[A]: spacecraft


[Q]: Sentence1: Oxidation occurs readily during hot weather. 
Sentence2: iron oxidation occurs more when it's hot.
[A]:
occurs