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: killing microorganisms in food can be used to extend the shelf life of that food. 
Sentence2: Cooking can be used to extend the shelf life of food.
[EX A]: be

[EX Q]: Sentence1: natural magnetism is used for pointing north by a compass. 
Sentence2: For the ordinary compass, align to the North direction.
[EX A]: north

[EX Q]: Sentence1: mountains are formed by earthquakes. 
Sentence2: Here the rocks have been uplifted along earthquake faults to make a mountain.
[EX A]:
earthquakes