Final answer:
To open the airway in a single-rescuer scenario, the head tilt-chin lift technique should be used. It straightens the airway and is an essential part of first aid and CPR.
Step-by-step explanation:
To open the airway for breaths when a single rescuer is present, one should utilize the head tilt-chin lift maneuver. This technique involves gently tilting the victim's head back and lifting the chin upwards, which helps to straighten the airway by pulling the tongue away from the back of the throat. This can be critical in ensuring that air can flow into the lungs without obstruction.
It is a common and effective method taught in basic first aid and cardiopulmonary resuscitation (CPR) courses, and is preferred over other methods such as nasopharyngeal airways or intubation, which are typically performed by medical professionals.