State the purpose of a System Sequence Diagram.

The purpose of a System Sequence Diagram (SSD) is to depict the flow of messages or interactions between system objects or actors in a particular use case. It helps to identify and visualize the sequence of events or actions that occur within a system and how they relate to each other. SSDs serve as a means to understand and communicate the behavior of a system and can be used during the analysis and design phases of software development projects.