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: Acids dissolve in base and turn blue litmus red. 
Sentence2: acid changes color.
[EX A]: Acids

[EX Q]: Sentence1: Tree-ring dating the 1700 Cascadia earthquake. 
Sentence2: estimating the age of trees can be used in reviewing earthquake history.
[EX A]: earthquake

[EX Q]: Sentence1: Heat is very important in cooking. 
Sentence2: Cooking an egg causes a chemical reaction in the egg.
[EX A]:
cooking