Final answer:
Disorder occurs spontaneously in systems, meaning it happens naturally without external energy input. For nonspontaneous processes to happen, energy must be input.
Step-by-step explanation:
A process that arises spontaneously doesn't require constant energy input from outside sources. In the case of disorder, systems tend to become more disorderly or disordered spontaneously. This means that disorder occurs spontaneously in systems. For example, if you have an organized stack of books on a table and you leave them untouched, over time, they might naturally become disordered and scattered.
On the other hand, nonspontaneous processes require continual input of energy to occur. Therefore, disorder in a system would not occur nonspontaneous.