A student is uploading files from a phone to a server on another network. Which layer of the TCP/IP model is responsible for addressing the data transmission?

The Internet layer of the TCP/IP model is responsible for addressing the data transmission as it manages the routing of packets through different networks. This layer encapsulates data into packets and attaches the necessary IP addressing information, allowing packets to be properly directed to their intended destination across interconnected networks.

In the given scenario, the student is uploading files from a phone to a server on another network. The Internet layer handles the critical task of finding the best path through the various networks between the source and destination by using IP addresses. This layer ensures that packets reach the correct end device, regardless of how many intermediate devices or networks they traverse.

While layers like the Application layer deal with user interface and data representation, and the Transport layer manages data transfer between systems for reliability and flow control, it is the Internet layer that specifically focuses on addressing and routing the data. The Network interface layer is responsible for the physical transmission of data over a specific medium, but it does not deal with addressing across different networks. Thus, the Internet layer is indeed the correct choice for the addressing aspect of data transmission in this context.