In the context of designing robust and adaptable software systems, one of the key principles is the separation of concerns between the （ ） aspects of the system. According to the principles of Domain-Driven Design (DDD), the core domain logic, which includes business rules, processes, and data manipulation, should be separated from the （ ） functionalities, such as data persistence, user interface, and external services integration. This separation ensures that the core domain logic remains focused and free from the complexities of infrastructure concerns. By adhering to this principle, developers can achieve a system that is more （ ）, allowing for easier maintenance, scalability, and adaptability to changing requirements. However, implementing this separation effectively requires a clear understanding of the domain and technical boundaries, as well as the ability to （ ） these boundaries in a way that minimizes coupling and maximizes cohesion. Despite the challenges, this approach has been （ ） in many successful software projects.