Which of the following is included in the steps of scene size-up?

The correct choice highlights the importance of ascertaining the need for additional resources during the scene size-up process. Scene size-up is a critical first step in any emergency response, allowing EMTs to evaluate the scene's safety, potential hazards, and the overall situation before engaging in patient care. Determining the need for additional resources, such as more personnel, firefighting equipment, or advanced medical assistance, is essential in ensuring that the response is effective and safe for both the responders and the patients involved.

Establishing the patient's medical history, performing a physical examination, and assessing the patient's vital signs are all crucial components of patient assessment but are not part of the scene size-up. These actions take place after the initial evaluation of the scene. Scene size-up focuses on understanding the context and environment surrounding the patient, preparing EMTs to provide care effectively.