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: Sex hormones are chemical messengers that control sexual development and reproduction. 
Sentence2: Androgens are male sex hormones.
[EX A]: Sex

[EX Q]: Sentence1: freezing means changing from a liquid into a solid by reducing heat energy. 
Sentence2: Water freezes into ice when cooled.
[EX A]: freezing

[EX Q]: Sentence1: Ethanol is produced by alcoholic fermentation of the glucose in corn or other plants. 
Sentence2: Ethanol qualifies as an alternative fuel.
[EX A]:
Ethanol