What describes the functionality of southbound APIs?

Refer to the exhibit. Traffic from R1 to the 10.10.2.0/24 subnet uses 192.168.1.2 as its next hop. A network engineer wants to update the R1 configuration so that traffic with destination 10.10.2.1 passes through router R3, and all other traffic to the 10.10.2.0/24 subnet passes through R2.
Which command must be used?
What are two benefits of private IPv4 addresssing? (Choose two.)
Which device separates networks by security domains?