Final answer:
The key underlying principle of Medical Resonance Therapy (MRT) Music is that music has healing properties. Music therapy can help manage symptoms, reduce stress, and improve overall quality of life.
Step-by-step explanation:
The key underlying principle of Medical Resonance Therapy (MRT) Music is that music has healing properties. It is believed that certain frequencies and rhythms of music can have a positive impact on a person's physical, emotional, and mental well-being. While music therapy can be a complementary approach to medical treatment, it is important to note that it is not a cure for diseases. Music therapy can help manage symptoms, reduce stress, and improve overall quality of life.