Which tier in the N-tier application architecture is responsible for moving and processing data between the tiers?

Application Layer is an informal or OSI networking term and does not specifically define the data-processing intermediary role in N-tier architecture.

The Data tier is responsible for persistent storage and retrieval of data, not for applying business logic or moving data between other tiers.

The Presentation tier handles rendering the user interface and collecting user input, not processing or routing data between architectural layers.

The Logic tier, also called the Business Logic or Middle tier, contains the rules that govern how data is created, stored, and modified as it flows between the user-facing Presentation tier and the back-end Data tier. It processes requests from the Presentation tier, applies business rules, and determines what data to retrieve or write via the Data tier. This separation ensures that business rules are centralized and not duplicated in the UI or database layers.