Final answer:
Step 3 of Trauma Field Triage Criteria involves making a list of known information, such as the type of radiation, energy per event, activity, and mass of tissue affected, to assess trauma severity.
Step-by-step explanation:
Step 3 of Trauma Field Triage Criteria involves making a list of what is known or can be inferred from the problem. In the context of this question, Step 3 specifically asks for information on the type of radiation, the energy per event, the activity, and the mass of tissue affected. By identifying these knowns, medical professionals can gather crucial information to determine the severity of trauma and provide appropriate care.