What type of development separates different aspects of a system?

Multi-tier development is a software architecture model that divides the system into distinct layers or tiers, each responsible for a specific aspect of the application’s functionality. This separation allows for a more organized structure, where each tier can be developed, maintained, and scaled independently. Typically, in a multi-tier architecture, there are at least three layers: the presentation layer (user interface), the application layer (business logic), and the data layer (database). This division not only enhances manageability and scalability but also facilitates clear communication between different components, leading to improved performance and flexibility in updates or enhancements.

In contrast, the other development models have different focuses. Sequential development, for example, follows a linear approach where each phase of development is completed before moving on to the next; it doesn't inherently separate functionalities into different layers like multi-tier architecture does. Single-tier development encompasses an all-in-one approach where all components are housed within a single layer, which can limit scalability and flexibility. Lastly, iterative development is characterized by repetitive cycles of development and refinement but does not emphasize the structural separation of system aspects as in multi-tier architecture. Thus, multi-tier development stands out for its strategic separation of system components.