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: Weather Clear weather usually means good visibility. 
Sentence2: High pressure systems can cause good visibility.
[A]: good


[Q]: Sentence1: Mollusks are invertebrates such as the common snail. 
Sentence2: snails have no backbone.
[A]: snail


[Q]: Sentence1: nuclear reactions in stars causes stars to produce light. 
Sentence2: Stars convert mass to energy.
[A]:
stars