Final answer:
The next step after assessing an unresponsive victim without breathing is to begin chest compressions.
Step-by-step explanation:
When assessing an unresponsive victim, the first step is to establish the scene's safety. After ensuring safety, you should quickly check the victim's responsiveness and breathing. If there is no response and the victim is not breathing, the next thing you should do is begin chest compressions. CPR, which stands for cardiopulmonary resuscitation, is a life-saving technique that helps maintain blood flow to the vital organs until medical help arrives. By applying pressure on the chest, specifically on the sternum between the lines at T4 and T9, you can compress the heart and push blood into the circulation.