Combining Db mirroring and Replication

Hi Team,

Can anybody help me understand why do one go combination of Database Mirroring + Replication.
Why can't I just have Database mirroring for high availability of my database. What is the need of combining replication as well.
In what scenario's we choose combining both these technologies.
Can anyone give an example of combining these 2 technologies ?
I am not sure if people a make things complex combining all high availability solutions. ( Clustering + db mirroring + replication)

Thanks in advance.