Multiple choice

A man will be unconscious if the blood supply to the brain is stopped for more than

  1. 2 seconds

  2. 5 seconds

  3. 10 seconds

  4. 30 seconds

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

Brain requires continuous oxygen supply. Blood supply interruption for more than 5 seconds causes unconsciousness due to rapid depletion of oxygen and glucose in neurons. Permanent damage begins within minutes.