What signal might rescuers respond to when someone is trapped?

Rescuers typically respond to a whistle as it is a clear and effective signal that can be heard from a distance. Whistles can produce a loud sound that carries over distances, making it easier for rescuers to pinpoint the location of someone trapped, especially in noisy environments or during disasters where other sounds may be overwhelming.

Using a whistle is also advantageous because it conserves energy while providing a consistent sound that can be repeated without fatigue, allowing the trapped individual to signal for help over an extended period. This makes it a practical and recommended tool in emergency situations for attracting attention and alerting rescuers to one's location.

In contrast, while voices shouting can signal for help, they may not be as effective due to the difficulty in locating the source of the sound in chaotic environments. Horns honking would typically be associated with vehicular situations rather than human distress, and cell phone alerts, while useful for communication, may not be reliable if the individual is unable to access their phone or if there is no signal in the area. The whistle stands out as the most reliable and effective signal for someone trapped to elicit a quick response from rescuers.