The root "echo" means?

• A. Reflect signal
• B. Running
• C. Pain
• D. From

Answer: (A)

Echo as a root refers to a reflected sound signal. In medical terminology, echo- denotes phenomena involving sound waves that bounce back from tissues. This is exactly what echocardiography uses: ultrasound sends sound into the chest and images the heart by interpreting the echoes that return from the heart structures. The other ideas—running, pain, or origin—don’t relate to echo, which is why the meaning is about reflected sound.