Why do my ELBs have two IP addresses? How to find them?

I have both application and classic internal load balancers running over a VPC. Each of them are associated to three subnets, on different availability zones, and almost each of them point to only one instance (in my case ECS containers).

But when issuing a nslookup command (nslookup internal-MYLB.us-east-1.elb.amazonaws.com)

I can see that output:

Server:     10.xxx.xxx.37
Address:    10.xxx.xxx.37#53

Non-authoritative answer:
Name:   internal-MYLB.us-east-1.elb.amazonaws.com
Address: 10.xxx.xxx.187
Name:   internal-MYLB.us-east-1.elb.amazonaws.com
Address: 10.xxx.xxx.204

For each load balancer, wether it's a classic or application one, two IP addresses are associated to its domain name.

I was simply wondering:

1. Does it correspond to two load balancer nodes for each load balancer? (Maybe I missed it but I didn't find that info in their doc)
2. Does AWS systematically spawns that for redundancy? Is it configurable?
3. Is there some way in the UI to see those IP addresses (I didn't find them in the UI or by using aws elb describe-load-balancers)

For the context, we have a remote partner who experiment issues with only one of the two IP addresses associated to a load balancer, maybe something like a network conflict due to some overlapping subnet range, but I'd prefer to be sure of what I see first.