What is the role of architectural layers in Flutter application development and why are they necessary?

Architectural layers in Flutter applications help separate responsibilities and simplify code maintenance. Typically, several layers are distinguished:

• Presentation (UI) — responsible for displaying the interface and user interaction.
• Business Logic — contains the application's logic, data processing, and rules.
• Data Layer — responsible for data retrieval and storage (e.g., working with APIs or databases).

This separation allows:

• Easier testing of individual parts of the application.
• Improved readability and maintainability of the code.
• Reuse of components.

For example, when changing the method of data retrieval, it is enough to modify only the Data Layer without affecting the UI.