Final answer:
The post-incident activity phase of the incident response process involves determining what happened, why it happened, and implementing measures to prevent it from happening again.
Step-by-step explanation:
The phase of the incident response process where we determine what happened, why it happened, and what we can do to prevent it from happening again is Post-incident Activity.
This phase occurs after the incident has been contained and the initial detection and analysis have taken place. It involves conducting a thorough investigation into the incident, identifying the root causes and vulnerabilities that allowed it to occur, and implementing measures to prevent similar incidents in the future.
For example, if a company experienced a data breach, the post-incident activity would involve forensic analysis to determine how the breach occurred, reviewing security protocols and implementing stronger measures to safeguard sensitive data, and educating employees on best practices for data protection.