Answer: four.
- A four
- B two
- C three
- D one
Correct answer: A. four
Explanation: The human heart has four chambers: two atria and two ventricles.
A single ECG cycle: the P wave marks atrial depolarisation (contraction signal), the large QRS complex marks ventricular depolarisation, and the T wave marks ventricular repolarisation (recovery) before the next cycle begins.
Concept context
Blood, lymph, the heart, the cardiac cycle, blood pressure, and ECG. High NEET weightage.