Sophia is a third-generation italian. she heard stories about how her grandparents experienced discrimination when they arrived in the united states. her grandparents also maintained their culture and traditions by continuing to speak italian in addition to leaning english. sophia knows very little about italian culture and does not speak italian. what accounts for this lack of cultural knowledge?

I believe the answer is: Sophia's grandparents and parents gradually assimilated, taking on the traditions of their new country.

Assimilation refers to the process where two or more different cultures interract with one another and form one mixed culture as a result.
When this happen until the next generation, children that are born on the next generation would tend to be not aware on the original/traditional culture where they came from.