DATA RECOVERY AFTER CRUSH

Hello, Tom! My colleague and I were discussing a scenario in Oracle 19c, and we had differing opinions, so we'd appreciate your insight. In an Oracle 19c database, consider the following scenario: User A performs data modifications and commits the changes. User B performs data modifications but does not commit the changes. Shortly after, the database experiences a crash. Upon recovery of the database, will the uncommitted changes made by User B be recoverable, or will they be lost? Could you explain the behavior of committed and uncommitted transactions in this context, and how Oracle handles these during the recovery process? Thank you in advance! Sincerely, Ainara