Validation primarily focuses on black-box testing, where the internal structure of the software is not considered, but its functionality is validated against user requirements. Verification is associated with white-box testing, where the internal code structure is examined for correctness and adherence to design.

Quality Assurance in Agile involves regular status meetings to discuss any issues or changes needed in the ongoing project. These meetings help ensure that the project aligns with its goals and that quality is maintained.

The Monolithic architecture style has a single codebase, and it is often easier to deploy as the entire application is packaged as a single unit. This simplicity can make deployment and maintenance more straightforward.

In a dynamic market environment, where frequent changes are expected, it is essential to apply software evolution models that are adaptable. Iterative models, such as Agile methodologies, allow for incremental and flexible development, making them a strategic choice to manage changes effectively. They enable continuous adaptation to evolving requirements and market dynamics.

Reverse engineering plays a critical role in identifying and mitigating software security flaws. By discovering vulnerabilities, organizations can address them before malicious entities exploit these weaknesses, ultimately enhancing the security of their software systems.

To prepare a cloud-based application for irregular spikes in user traffic, stress testing should be strategically employed. Automated tools can simulate these spikes to observe how the system behaves under such conditions. This helps identify any performance bottlenecks and ensure consistent performance.

The principle suggesting that derived classes must be substitutable for their base classes is "Polymorphism." It allows objects of derived classes to be used where objects of the base class are expected, enabling flexibility and extensibility in software design.

A compliance audit is performed to ensure that all contractual agreements, legal requirements, and specified standards have been fulfilled. In the context of software engineering, this type of audit is crucial to confirm that the product adheres to all requirements and agreements.

Preventive maintenance focuses on anticipating and preventing issues before they occur. It involves tasks such as code reviews, proactive bug-fixing, and performance optimization to maintain the system's reliability.

Regression testing is typically performed after code changes are made and before a new release or update of the software. It ensures that existing functionality remains intact after modifications.