Final answer:
The urbanization in America led to the development of settlement houses due to poor living conditions and widespread illness in tenement houses, affecting the working-class and immigrants.
Step-by-step explanation:
The problem caused by rapid urbanization in America that led to the development of settlement houses was the dire living conditions experienced by the working-class and poor immigrant families in the cities.
These families often resided in tenement houses with insufficient sanitation, leading to widespread illness. Within these overcrowded slums, diseases such as tuberculosis and pneumonia spread rapidly due to the poor living conditions and lack of proper infrastructure.
In response to these challenges, settlement houses were established by social reformers, like Jane Addams and Lillian Wald, to provide support such as free health care, education, and better housing options to alleviate some of the struggles faced by the urban working class.