What mechanism is used to retrospectively record and examine data changes in information systems?

The mechanism used to retrospectively record and examine data changes in information systems is audit controls. Audit controls are essential for tracking modifications made to data over time, allowing organizations to monitor alterations, verify data integrity, and ensure compliance with regulations. They involve logging events such as who made changes, when they were made, and what specific changes occurred. This creates a historical record that can be reviewed to detect any inappropriate or unauthorized activities, contributing to both security and accountability within the information system.

In contrast, the other options serve different functions. Data warehousing is primarily concerned with storing and managing large volumes of data for analysis, not specifically focused on tracking changes. Backup processes provide a method for protecting data against loss but do not inherently record the details of changes made. Input validation ensures that incoming data meets certain criteria for accuracy and quality, which helps in preventing incorrect data from entering the system but does not relate to retrospective examination of modifications.