Which machines can be configured by using the configuration Wizard?

Consider an application that comprises both web and EJB components.
What are two benefits of implementing a multitier cluster architecture over a single-tier(basic) cluster
architecture? (Chose two.)

You are using the Configuration Wizard to create a now domain that will consist of a cluster of a of three managed servers along with an instance of WebLogic server acting as HIPT proxy to distribute traffic to the cluster.
Which three steps should you perform with the Configuration Wizard?

One of your applications sends SQL requests to a back-end database. Today some of these requests are very slow to complete and users are waiting an unusually long time before getting the information back. You decided to take a look at a thread dump and found several threads with a stack similar to:

What should be your initial assumption and first action?

In your WebLogic Server environment, applications will not access a single database server. Instead they will access a cluster of redundant database servers. This database product was purchased from a vendor other than Oracle. You want to provide transparent failover to the applications as they communicate with the database cluster. Which type of WebLogic data source should you create?