Final answer:
Gerda's parents didn't look back at their home when leaving for the ghetto to avoid emotional pain, while Gerda looked back perhaps to acknowledge her past and affirm her memories during a forced and traumatic change.
Step-by-step explanation:
Gerda's parents likely refuse to look back at their old home when they leave for the ghetto because looking back could be a painful acknowledgment of the life they are leaving behind and the uncertainty of their future. This act of not looking back can be a way to try to avoid the emotional pain associated with their loss.
On the other hand, Gerda chooses to look back probably as a way to affirm her memories, to acknowledge her past, and perhaps as a gesture of defiance or a form of silent farewell.
In moments of forced change or exile, different people react in different ways to the trauma: some may choose to deny its impact, at least momentarily, while others may confront it directly, even if it causes more immediate pain.