Can a VNet span multiple Azure regions?

No, a single Azure VNet cannot span multiple Azure regions, it is limited to a single region.

Which IP classes are used for normal host addressing?

Class A, Class B, and Class C.

How does NAT use public and private IP addresses?

NAT uses public IP addresses for external internet access by translating the private IP addresses of devices on a local network.

Can a device have multiple public or private IPs?

Yes, a single device can have multiple public and/or private IP addresses simultaneously.

Can private IP addresses be routed over the internet?

No, private IP addresses cannot be routed over the public internet because they are reserved for use within private networks.