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: an animal requires air for survival. 
Sentence2: The Moon has no atmosphere and no air.
[EX A]: air

[EX Q]: Sentence1: high pressure systems cause clear weather. 
Sentence2: Weather Clear weather usually means good visibility.
[EX A]: clear

[EX Q]: Sentence1: Heterotrophs are living things that cannot make their own food. 
Sentence2: animals cannot make their own food.
[EX A]:
cannot