Why is the Physical Link at Layer 1 of the OSI? Cellular towers relay information Copper wiring transmits the electrical signal Data is checked to make sure it is complete The sender is identified

The Physical Layer (Layer 1) of the OSI (Open Systems Interconnection) model is primarily concerned with the physical connection between devices and the transmission of raw binary data over a physical medium. The reasons given in the question are associated with different layers of the OSI model:

1. Cellular towers relay information:

• This is related to the Data Link Layer (Layer 2) or higher layers of the OSI model. The Data Link Layer deals with the reliable transmission of frames between devices on the same local network.

2. Copper wiring transmits the electrical signal:

• This is directly related to the Physical Layer (Layer 1). The Physical Layer deals with the physical medium, such as copper wiring, optical fibers, or wireless frequencies, and how raw bits are transmitted over these media.

3. Data is checked to make sure it is complete:

• This is associated with the Data Link Layer (Layer 2) or higher layers. The Data Link Layer often includes error-checking mechanisms to ensure the integrity of the data during transmission.

4. The sender is identified:

• This is associated with the higher layers of the OSI model, particularly the Network Layer (Layer 3) and above. The Network Layer deals with logical addressing, routing, and the identification of devices on different networks.