At which layer does human interaction with data occur in the OSI model?

The Application Layer is the highest level in the OSI model, and it is where human interaction with data primarily occurs. This layer provides the interface through which users and application processes can communicate over a network. It encompasses various protocols that facilitate user applications and services, such as web browsers, email clients, and file transfer programs.

In this layer, users interact directly with the data through these applications, making it essential for providing a meaningful experience. The protocols at this level ensure that the data presented to users is organized and correctly formatted, enabling effective communication and functionality.

The other layers, such as the Session, Transport, and Network Layers, play crucial roles in managing data transmission and ensuring reliable communication, but they do not directly involve user interaction. Instead, they handle tasks like establishing sessions, data segmentation, and routing, which are vital for data transfer but occur behind the scenes, away from the direct engagement of human users.