Implementing Cisco IP Switched Networks (SWITCH v2-0) (#424)

Which two reasons to deploy UDLD on a switch are true? (Choose two.)

It can interact with Layer 2 mechanisms to monitor the status of physical links
It can prevent forwarding loops that result from unidirectional links.
It can interact with Layer 1 mechanisms to monitor the status of physical links
It can replace the Cisco Discovery Protocol
It can replace spanning tree