About seventy-eight organs make up the human body—each one with a different function (or sometimes the same, as with two kidneys), size, function, and sometimes shape. The largest organ, with respect to its size and weight, in the human body is the skin. Not everyone has organs in the same place, either; for example, sometimes organs such as the kidney may be located closer to the pelvis, or only one kidney may be present. These differences can be due to genetics, difference in the growth of cells of that organ, or even disease.