Final answer:
The Presentation Layer of the OSI model structures messages and translates data formats for applications.
Step-by-step explanation:
The layer of the OSI model that is responsible for structuring messages for the application and translating if necessary is the Presentation Layer. The Presentation Layer ensures that the data is in a usable format and is where data encryption, compression, and translation between different data formats happens. It acts as a translator between the data formats on the network and the application layer. This layer is essential for seamless communication between different systems that may use different data representations.