AngularJS utilizes Two-way Data Binding to automatically update the view when the model changes. Two-way Data Binding establishes a bidirectional link between the model and the view, ensuring that any changes in one reflect immediately in the other. This feature simplifies the code, reduces the need for manual DOM manipulation, and enhances the overall efficiency of AngularJS applications.

Structural directives in AngularJS, such as *ngIf and *ngFor, control the structure of the DOM by adding or removing elements based on certain conditions. They can alter the layout of the page and dynamically change the structure of the view. Understanding the distinction between structural and attribute directives is crucial for effective template manipulation in AngularJS applications.

Modularization and dependency injection in AngularJS facilitate code maintenance and scalability by reducing code coupling and promoting reusability. Modularization helps in organizing code into separate modules, while dependency injection allows components to be loosely coupled, making it easier to manage and scale the application. Understanding these concepts is crucial for building scalable and maintainable AngularJS applications.

In AngularJS, controllers are defined using the controller keyword. This can be done within the HTML markup or in a separate JavaScript file, depending on the application's structure. Defining controllers helps organize the code and encapsulate the logic related to a specific part of the application. Knowing the correct syntax and usage of the controller keyword is essential for proper implementation in AngularJS projects.

AngularJS's post method in the $http service is used to make a POST request to an external API. This method is crucial for sending data to a server, such as submitting a form or creating a new resource. Understanding how to use the post method is essential for handling data communication in AngularJS applications.

The .config() method in AngularJS modules is used for module configuration. It allows developers to perform configuration tasks, such as setting up providers and decorators, before the module is run. This method is invoked during the configuration phase of AngularJS's application lifecycle, providing an opportunity to customize the behavior of the module. Understanding the role of .config() is essential for fine-tuning module behavior in AngularJS applications.

The primary purpose of directives in AngularJS is to extend HTML with new attributes and elements. Directives are markers on a DOM element that tell AngularJS to attach a specific behavior to that DOM element or transform it. They play a crucial role in enhancing HTML functionality and enabling the creation of reusable components in AngularJS applications. Understanding directives is fundamental to building dynamic and interactive user interfaces.

Data binding in AngularJS controllers relies on the digest mechanism to update the view. The digest cycle is a core part of AngularJS's two-way data binding system. During the digest cycle, AngularJS checks for changes in the model and updates the view accordingly. Understanding the digest cycle is crucial for efficient data binding in AngularJS applications.

Using AngularJS expressions within HTML attributes, such as event handlers, class attributes, and form validation, can enhance user interaction and experience. These expressions allow developers to create dynamic and responsive user interfaces. For example, updating UI elements based on user actions, dynamically applying styles, and providing real-time feedback in forms contribute to a more engaging and user-friendly experience. This understanding is crucial for leveraging AngularJS expressions effectively in different scenarios.

In AngularJS, the business logic should ideally be placed in a Service. Services are responsible for encapsulating and organizing business logic, data manipulation, and other functionalities that are not directly related to the view or user interactions. By placing business logic in services, AngularJS promotes reusability, maintainability, and testability of code. Understanding the role of services is key to building scalable and modular AngularJS applications.