You will be given a definition of a task first, then some input of the task.
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.

Sentence1: Astronauts go out into space. 
Sentence2: those who go out into space require preserved food for extended flights.
Output:
go