A mole is a collection of skin cells containing an unusually high level of the skin pigment known as melanin. Most moles are acquired traits, appearing during the first two decades of a person's life. In the image below, a doctor is examining a mole on a male patient's back.

Most moles are the result of an error in
during the production of a

Most moles are the result of an error in melanocyte production during the production of a skin cell.