Final answer:
The subject of this question is Incident Command System (ICS) in Social Studies, which involves the coordination of multiple response agencies in a large-scale incident.
Step-by-step explanation:
In the field of Social Studies, the subject of this question is Incident Command System (ICS). ICS is a standardized approach to coordinate the efforts of multiple response agencies involved in a large-scale incident or emergency situation. It includes the establishment of a Unified Command, which is a single command structure formed by Incident Commanders from various jurisdictions or agencies operating together.