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: the emission of sulfur dioxide causes acid rain. 
Sentence2: Sulfur dioxide emissions causes soil nutrients to be leached away.
[EX A]: dioxide

[EX Q]: Sentence1: Earthquakes are natural disasters. 
Sentence2: earthquakes can cause animals to leave an environment.
[EX A]: Earthquakes

[EX Q]: Sentence1: high mountains with well-rounded peaks can be formed by collision of crustal plates. 
Sentence2: On Earth, volcanoes are found mainly along the colliding boundaries of great crustal plates.
[EX A]:
crustal