Thank you for posting in Symantec community.
I would be glad to answer your query.
1.In symantec Backup what is excact contents in the Backup.
---> When you perform a backup it prompt to include logs as well. So it depends what you had choosen while taking backup.
Normal backup contains All the SEPM policies, Group structure including client information & other settings as well except communication settings. To restore the communication you would required recovery file.
http://www.symantec.com/docs/HOWTO55107
2.In replication what all contents are relicated ( keeping logs and contents both enabled)
--> It depends what you have choose to replicate.
Q3: What data is replicated?
A3: Policies, clients, and groups always get replicated. Logs ("Replicate logs from the local site to this partner site"), and packages and definitions ("Replicate client packages and LiveUpdate content between the local site and the partner site") are optional. Also the initial replication will replicate the entire database, and then subsequent replications will only replicate changed data based on the USN number in the database and the items selected.
Reference: http://www.symantec.com/docs/TECH93107
3.what is the dependency of SQL database for our Symantec SEPM application.
--> SQL database version should be in the supported list provided by Symantec.