Final answer:
At the start of an emergency operations center, the essential components include policies, procedures, communications means, and maps, but not the recovery plan, which is focused on post-emergency restoration.
Step-by-step explanation:
The essential activation components required at the start of an emergency operations center (EOC) include policies, plans, procedures, and checklists; primary and backup means of communications; and maps and utility diagrams. These elements are fundamental to ensuring a coordinated response during an emergency. However, the recovery plan is typically not an essential component to begin operations at an EOC. The recovery plan is more about restoring normalcy after the immediate emergency has passed, rather than the initial activation and operational phase of the EOC.