Final answer:
In The Zookeeper's Wife, Rys first hears about the impending war through his parents' increasing concern about the political situation in Europe, notably Warsaw's danger of becoming a battleground.
Step-by-step explanation:
In The Zookeeper's Wife by Diane Ackerman, Rys, the son of Jan and Antonina Zabinski, first hears about the impending war when his parents start to express their concerns about the political situation in Europe. This is because Warsaw, where they live and manage the city's zoo, is in danger of becoming a battleground. The Zabinskis, aware of the looming threat, attempt to prepare themselves and the zoo for possible conflict, and it is thus how Rys is initially made aware of the precarious situation.
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