Answer:
Bridges and switches
Step-by-step explanation:
4a) A bridge is an intelligent repeater that is aware of the MAC addresses of the nodes on either side of the bridge and can forward packets accordingly.
A switch is an intelligent hub that examines the MAC address of arriving packets in order to determine which port to forward the packet to.
4b) Twisted-pair cable is a type of cabling that is used for telephone communications and most modern Ethernet networks