Final answer:
The Pennsylvania System, also known as the separate or solitary system, was a new approach to prison reform in the 19th century. The Walnut Street Jail in Philadelphia became the model of this system.
Step-by-step explanation:
The Walnut Street Jail in Philadelphia became the model of the Pennsylvania System.
The Pennsylvania System, also known as the separate or solitary system, was a new approach to prison reform in the 19th century. It aimed to rehabilitate prisoners through isolation and hard labor.
Under the Pennsylvania System, prisoners were kept in individual cells for most of the day and were only allowed out for solitary exercise. They were also required to engage in productive work, such as making shoes or weaving textiles.