A teenager has collapsed at a friend's house and is not responding. What is the first life-saving step to take?

While ensuring the teenager's comfort may seem considerate, it does not address the immediate life-threatening situation. The priority in an unresponsive scenario is to secure emergency help rather than focus on comfort measures, which could delay essential care.

Starting chest compressions may be necessary if the teenager is in cardiac arrest, but before initiating CPR, it is vital to call 911. This allows emergency services to be on their way while the responder can begin lifesaving techniques, ensuring that help arrives as soon as possible.

Searching for the teenager's parent can significantly delay critical care. In emergencies, it is essential to prioritize calling for professional medical help immediately rather than attempting to locate family members, who may not be able to provide the necessary assistance on-site.