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: Oil and gasoline are fossil fuels. 
Sentence2: lawn mowers convert fossil fuels into motion.
[EX A]: fossil

[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: Steroid hormones are made of lipids, such as phospholipids and cholesterol. 
Sentence2: Steroid hormones are made of diverse hydrophobic molecules, such as phospholipids and cholesterol.
[EX A]:
Steroid