Multiple choice

ECG records

  1. rate of heart beat

  2. volume of blood pumped

  3. heart diseases

  4. potential difference of cardiac muscle

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

ECG (Electrocardiogram) records the electrical activity of the heart over time, specifically the potential difference (voltage changes) of the cardiac muscle. This is detected through electrodes placed on the skin. It does not directly record rate, volume, or diseases.