In AngularJS, two-way data binding is a part of its _________ architecture, allowing seamless data flow.

In AngularJS, two-way data binding is a part of its Model-View-ViewModel (MVVM) architecture. The MVVM architecture extends the traditional MVC pattern by introducing a ViewModel, which enhances data binding capabilities. The ViewModel in AngularJS acts as an intermediary between the Model and the View, facilitating efficient two-way data binding and ensuring a smooth flow of data between the application's logic and the user interface. Understanding the MVVM architecture is fundamental for leveraging the full power of two-way data binding in AngularJS.