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: wind is used for producing electricity. 
Sentence2: Winds are caused by pressure differences.
[A]: wind


[Q]: Sentence1: Mitosis is cell division. 
Sentence2: mitosis often causes growth.
[A]: Mitosis


[Q]: Sentence1: Combustion of fuel is one of the main causes of air pollution. 
Sentence2: high temperatures can cause air pollution.
[A]:
air