What are facts for medical?
* The lungs hold about 5 liters of air.
* The brain uses about 20% of the body's total energy.
* The stomach can hold about 1 liter of food.
* The intestines are about 25 feet long.
* The kidneys filter about 1.3 liters of blood every minute.
* The liver weighs about 3 pounds.
* The skin is the largest organ in the body.
* The body contains about 60,000 miles of blood vessels.
* The human body is made up of about 100 trillion cells.