Accountability is the responsibility of individuals and systems to track and log their actions and activities related to the handling and accessing of data. It ensures that every action taken on a system can be traced back to a specific user or process, allowing for auditing and monitoring of security-related events. This helps detect and prevent unauthorized actions, ensures compliance with security policies, and supports investigations if a security breach occurs. Accountability mechanisms include audit trails, user activity monitoring, and file activity monitoring, which together maintain the integrity and security of information systems.