The adult human brain weighs on average about 3 lb. (1.5 kg) with a size of around 1130 cubic centimeters (cm3) in women and 1260 cm3 in men, although there is substantial individual variation. Men's brains are on average 100g heavier than a woman's, even when corrected for body size differences The brain is very soft, having a consistency similar to soft gelatin or firm tofu. Despite being referred to as "grey matter", the live cortex is pinkish-beige in color and slightly off-white in the interior. The photo on the right shows a horizontal slice of the head of an adult man, from the National Library of Medicine's Visible Human Project. In this project, two human cadavers (from a man and a woman) were frozen and then sliced into thin sections, which were individually photographed and digitized. The slice here is taken from a small distance below the top of the brain, and shows the cerebral cortex (the convoluted cellular layer on the outside) and the underlying white matter, which consists of myelinated fiber tracts traveling to and from the cerebral cortex. At the age of 20, a man has around .......