Final answer:
Under critical level of service, firefighters prioritize life safety and property conservation by focusing on rescue, evacuation, and fire suppression to save lives and protect the affected area.
Step-by-step explanation:
Under critical level of service, firefighters are expected to revert to emergency response strategies that prioritize life safety and property conservation. This means that when faced with a critical situation where resources are limited, firefighters will focus on rescuing people and mitigating further damage to property. They may prioritize tasks such as search and rescue, evacuation, and fire suppression in order to save lives and protect the affected area.