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: burning fossil fuels increases the carbon in the atmosphere. 
Sentence2: the byproduct of fossil fuels is carbon.
[EX A]: carbon

[EX Q]: Sentence1: a rainbow is formed by refraction of light by separating light into all different colors. 
Sentence2: Rainbows form when raindrops refract sunlight.
[EX A]: refraction

[EX Q]: Sentence1: wiring requires an electrical conductor. 
Sentence2: Ground wire acts as an extra conductor.
[EX A]:
wiring