Hello,

The largest internal organ in the Human body is the liver. The use of liver is, it will filter the blood coming from the digestive tract before going into other body parts. The liver has two large sections called Right and Left lobes. The liver works to digest, absorb and process the food. The liver makes the proteins important for blood clotting and other functions. 

The largest external organ in the human body is skin. Human skin is the outer cover of the body the skin has upto seven layers human skin is similar to most of other mammals skin. Melanin is the pigment which will present in the human skin which will make changes in the contrast of human skin. Due to melanin there will be contrast difference between one other.

Thank You.