For a widget that should update its appearance based on user interaction, you would likely use a ______ widget.

For a widget that should update its appearance based on user interaction, you would likely use a 'StatefulWidget.' 'StatefulWidget' is used when the internal state of a widget can change, and the widget needs to be rebuilt to reflect those changes. This is essential for creating dynamic and interactive user interfaces in Flutter. Understanding the role of 'StatefulWidget' is crucial for handling stateful components in Flutter applications.