Which of the following is true regarding web blocks?

Web blocks in OutSystems are reusable components that allow developers to encapsulate both UI and logic in a modular way. This means that a web block can include its own client-side logic, such as conditions for rendering elements, handling events, and managing state. By encapsulating logic within a web block, developers can create more maintainable and organized code, facilitating reuse across different parts of an application.

This characteristic of web blocks enables them to act like mini-components, where you can define specific behavior and presentation independently from the rest of the application. Such encapsulation is vital in larger applications where multiple UI elements with related functionalities need to work together without intertwining their logic excessively.

Other options fall short of this definition. For example, web blocks can be created without any mandatory instantiation in certain contexts, and they certainly do not need to be visible on the page at all times. Thus, the ability to include encapsulated logic is a key feature that defines and enhances the functionality of web blocks within the OutSystems framework.