how does ritual and religion play an important part in the survival of the Jews?

Hannah initially demonstrates an apathy toward her own heritage. She has no interest in going to the Passover Seder dinner and sees it as something to be endured rather than to be celebrated. Prior to the dinner she spends time at her friend Rosemary's house, where she eats a meal ahead of time. Rosemary is not Jewish and Yolen implies that Hannah actively avoids anyone of a similar background to her own.

The Passover Seder is a ritual designed to commemorate the past and those who have come before. Hannah has little interest in its origins or relevance in the present. It is not until she is torn from her own family and transported to a dark period in history that Hannah comes to appreciate her heritage. She is alive because of decisions and sacrifices that were made by others well before her own birth. If these sacrifices had not been made, she might never have existed.

This concept, that the present is a living product of the events of the past, echoes throughout the novel. Consider how casually Commandant Breuer decided who lived and who died in the camp. Without any real consideration, entire bloodlines and family trees were destroyed. As a result the families of survivors have a greater appreciation of their own lives, knowing that their ancestors were able to survive a horrific ordeal and should not be forgotten.

Hannah initially demonstrates an apathy toward her own heritage. She has no interest in going to the Passover Seder dinner and sees it as something to be endured rather than to be celebrated. Prior to the dinner she spends time at her friend Rosemary's house, where she eats a meal ahead of time. Rosemary is not Jewish and Yolen implies that Hannah actively avoids anyone of a similar background to her own.