Final answer:
The Pennsylvania System used solitary confinement, where inmates were kept apart from one another at all times, with daily activities taking place in individual cells.
Step-by-step explanation:
The subject of this question is History. The Pennsylvania System was a nineteenth-century penitentiary that used the system of solitary confinement. In this system, inmates were kept apart from one another at all times, with daily activities taking place in individual cells. This method aimed to reform and morally redeem criminals by isolating them from social vices and providing religious instruction and hard work.