According to CCNP BSCI(Cisco Press page 18) each server should connected with two switches for redundancy. That means each server must have at least two ethernet adapters.That means two IPs.
As i can understand if a client wants to connect to a server must put ip or name. If one link is down then the client must use other domain name or IP. So by using this desing we use cables and adapters only in case if one link is down . And even though we have to inform our clients to use a different domain name.
-Is there is a way to use both links and have load balance.
- Is there is a way to use a single domain name with two or more ips.
You need to visit the web site of the NIC vendor or you can go to the OS vendor's site eg. on Windows it's called "teaming" so if you did a search for that on the microsoft site you should get some config examples.