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: Most soil nutrients are cations. 
Sentence2: decomposition increases the amount of cations in the soil.
[EX A]: cations

[EX Q]: Sentence1: All oaks are trees. 
Sentence2: Cutting down oaks has a negative impact on an ecosystem.
[EX A]: oaks

[EX Q]: Sentence1: Lightning Occurs with ALL thunderstorms. 
Sentence2: Cold fronts cause lightning as they pass by.
[EX A]:
Lightning