Redo log files are used to roll back uncommitted transactions???

Which two statements concerning redo log files are true? (Choose two.)
1.Redo log files store committed changes to the database.
2.Redo log files are used to roll back uncommitted transactions.
3.Only one redo log file is required.
4.Changes are written to the redo log files when the redo log buffer is 3/4 full.
5.Redo log files are used instead of archiving for point-in-time recovery.

Apparently 1&2 are correct. But How can 2 be correct I don't understand:confused:

Cheers
Gus

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