Final answer:
The number of people of the ZOB who died on the first day of the German attack in the book 'Resistance' is not provided in historical records, but during the Warsaw Ghetto Uprising, about thirteen thousand Jewish people died in total.
Step-by-step explanation:
In the context of the book Resistance, on the first day of the German attack the number of people of the ZOB (Jewish Combat Organization) who died is not explicitly stated. However, historical records show that during the Warsaw Ghetto Uprising, the ZOB and other groups faced considerable losses against the Germans. On the first day of the main uprising on April 19, 1943, the Germans intended to liquidate the Warsaw Ghetto but were met with armed resistance. While exact casualties of the first day are hard to establish, the fierce clashes during the uprising eventually led to the deaths of about thirteen thousand Jewish people, with resistance continuing until mid-May. The losses of the ZOB were part of these numbers with many sent to concentration camps or killed during the fighting or after being captured. The Warsaw Ghetto Uprising was a significant act of resistance against the oppressive Nazi regime during World War II.