Application Properties let developers expose configurable values (via system properties), so behavior can be changed without altering code.
From Development Handbook 4.0.4, p. 167:
"Use application properties to enable or disable features or change behavior without modifying scripts directly. This promotes modularity and flexibility."

In ServiceNow, UI Actions are elements that facilitate user interaction within the platform, enabling users to perform specific actions such as form submissions, record updates, or triggering workflows. The valid types of UI Actions include:
Form Button: A button displayed on a form that, when clicked, executes a defined action.
Form Context Menu: An option added to the context menu of a form, providing additional actions related to the form's record.
Form Link: A hyperlink on a form that directs users to another page or executes a script.
List Banner Button: A button displayed in the banner area of a list, allowing actions to be performed on multiple records simultaneously.
List Choice: An option added to the list context menu for individual records, enabling actions on a selected record.
List Link: A hyperlink in a list that directs users to another page or executes a script.
Record Navigation Button: Buttons that facilitate navigation between records, such as Next and Previous buttons.
Options like "Workflow action" and "Form choice" are not recognized as standard UI Action types in ServiceNow.
For comprehensive details, refer to the official ServiceNow documentation on UI Actions.

The ServiceNow platform is designed to create applications that use forms, workflow, and reporting to solve business problems. Forms are used to interact with data stored in tables, workflow is used to automate and orchestrate processes, and reporting is used to visualize and analyze data. The platform does not require low-level programming libraries or multimedia features, as it provides standard tools and technologies for application development.
References = ServiceNow Certified Application Developer Exam Specification, Application Development Platform - ServiceNow

In ServiceNow, the Event Registry is a table that contains a record for every event recognized by the system.
It allows ServiceNow to respond when these events are generated. By registering events, the system can automate activities such as triggering notifications or executing script actions when specific events occur.
Therefore, the correct answer is A.
The other options are not accurate descriptions of the Event Registry:
* B. The Event Log which lists all Events that have been generated: This describes the Event Log, not the Event Registry.
* C. A Workflow which is launched every time an Event is generated; used to debug Events: This is not how the Event Registry functions.
* D. The method used in server-side scripts to generate Events and pass parameters: This describes the gs.
eventQueue() method, not the Event Registry.
For more detailed information, refer to the official ServiceNow documentation on the Event Registry.