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🔬 Biology  ·  Body Fluids and Circulation  ·  NEET

The average life span of a human red blood cell is about:

Answer: 120 days.

  • A 30 days
  • B 60 days
  • C 120 days
  • D 200 days

Correct answer: C. 120 days

Explanation: Human erythrocytes normally survive about 120 days before being destroyed in the spleen and liver.

ECG: The Three Key WavesP wave(atrial depol.)QRS complex(ventricular depol.)T wave(ventricular repol.)QRS is the tallest spike - ventricles have far more muscle mass than the atria

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.

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