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.

[Q]: Sentence1: Precipitation falls on the windward side of the mountain range. 
Sentence2: Mountains have higher precipitation than adjacent lowlands.
[A]: Precipitation


[Q]: Sentence1: Most soil nutrients are cations. 
Sentence2: decomposition increases the amount of cations in the soil.
[A]: cations


[Q]: Sentence1: astronauts require preserved food for extended flights. 
Sentence2: Space shuttle travelers require preserved food for extended flights.
[A]:
extended