For what two purposes does the Ethernet protocol use physical addresses? (Choose two.)

A.
to uniquely identify devices at Layer 2

B.
to allow communication with devices on a different network

C.
to differentiate a Layer 2 frame from a Layer 3 packet

D.
to establish a priority system to determine which device gets to transmit first

E.
to allow communication between different devices on the same network

F.
to allow detection of a remote device when its physical address is unknown