The prototype of a function includes the function's name, return type, and the types of its parameters. It provides a declaration of the function's signature, allowing the compiler to check function calls for correctness.

The main purpose of static analysis in software testing is to identify defects in the early stages without having to actually execute the code. This is beneficial as it helps in improving the quality of the code and reduces the cost of fixing defects at later stages.

Stress testing is a dynamic testing technique used to determine how a software system behaves under conditions that are not normal or expected, such as under extreme loads, limited memory, or when subjected to hacking attempts. Its main goal is to ensure the software doesn't crash in suboptimal conditions.

Usability Testing is a type of software testing where the primary focus is to ensure that the application is user-friendly, intuitive, and easy to understand. It ensures that the end-users can efficiently complete their intended tasks without facing unnecessary obstacles or confusions.

The "Exhaustiveness" principle suggests that it's impractical and non-feasible to test all possible combinations and scenarios in a software application due to constraints like time, resources, and the infinite possibilities. Instead, focused and effective testing is carried out based on risk and priority.

Dynamic testing techniques involve the actual execution of the software. It's performed when the code is run, as opposed to static testing which is performed without executing the code. Dynamic testing validates the software system in a runtime environment.

Usability testing is geared towards understanding how end-users interact with the software and ensuring a positive user experience. The primary considerations involve the system's ease of use, its consistency in design and functionality, and adherence to user interface design guidelines. UAT, on the other hand, determines if the system meets user needs, while load and compatibility have different focuses.

Security testing primarily aims to identify vulnerabilities, weaknesses, and potential threats in a software application. It is crucial for protecting data from unauthorized access and breaches, ensuring the confidentiality, integrity, and availability of the system.

Automated testing involves the initial cost of writing and maintaining scripts, making it not cost-effective for one-time testing scenarios. While automation can handle large-scale projects and performance testing, it's not recommended when the requirements change often.

Test levels, which include stages like unit, integration, system, and acceptance testing, play a critical role in the Test Planning phase. They help in organizing the sequence and scope of testing activities, ensuring that all components of the software are thoroughly evaluated at the appropriate stages.