Multiple choice general knowledge science & technology what is the weight of brain in body percent 4% 2% 6% 8% Reveal answer Fill a bubble to check yourself B Correct answer Explanation The human brain weighs approximately 2% of total body weight (about 1.3-1.4 kg in an adult), despite consuming about 20% of the body's oxygen and glucose. This makes it one of the most energy-demanding organs relative to its size.