Readability is a software quality metric that assesses the simplicity and clarity of the code in a software project. It focuses on how easy it is for humans to read and understand the code. Clear and simple code is essential for maintainability and collaboration among team members.

In the Client-Server architecture, services communicate via a well-defined interface using lightweight protocols. This architectural style is characterized by the separation of client and server roles, where clients request services from servers, which can be located on different machines or networks.

The Microservices architecture style provides a structured system that can be decomposed into smaller, reusable modules. In this architecture, the software is organized into small, independent services that communicate through APIs. This approach allows for greater flexibility and scalability in software development.

Adaptive maintenance focuses on making changes to the software to adapt to changes in the operating environment, such as hardware upgrades or new regulations. It ensures the software remains compatible with evolving external factors.

The cognitive model in UI design centers on predicting how users will interact with the interface by considering their past interactions and experiences. It delves into user psychology and cognitive processes to create interfaces that align with users' mental models and expectations.

Boundary Value Analysis, a Black Box Testing technique, is significant as it focuses on testing the boundary or extreme values of input conditions, which often reveal errors that might not be apparent when testing typical values.

Incorporating SQA practices into the software development process ensures that quality standards are met, which, in turn, leads to a more reliable product. A reliable product tends to result in higher customer satisfaction because it is less likely to have defects or issues.

Build Management in SCM contributes by automating the process of building software components. It ensures that the right code and dependencies are compiled, integrated, and packaged correctly, enhancing the consistency and reliability of the build process.

The primary purpose of the Observer design pattern is to maintain a one-to-many dependency between objects. This means when one object (the subject) changes its state, all its dependents (observers) are notified and updated automatically. It's commonly used in scenarios where you need to implement distributed event-handling systems or maintain consistent data across multiple objects.

Black Box Testing is called so because it symbolizes testing without any knowledge of the software's internal structure, just like a tester is working with a "black box" and doesn't need to see what's inside. This approach emphasizes testing solely based on external behavior.