Which of the following is NOT a fundamental of first aid?

The correct answer identifies "Diagnosis of illnesses" as not being a fundamental aspect of first aid. First aid primarily focuses on immediate, emergency interventions that can be administered at the scene of an injury or medical emergency. It encompasses the control of bleeding, responding to physical shock, and treating cuts, wounds, or burns.

The reason "Diagnosis of illnesses" is not considered a fundamental of first aid lies in its complexity. Diagnosis typically requires thorough medical training, assessment of patient history, and comprehensive examinations, which go beyond the scope of basic first aid. Instead, first aid aims to stabilize the situation and alleviate immediate dangers while waiting for professional medical help. First responders or individuals trained in first aid should focus on observable signs and symptoms rather than attempting to diagnose medical conditions, which can lead to mismanagement or inaccuracies in treatment.