What makes the fingerprints unique?
The fingertips on their underside have a unique pattern of ridges. Each person has his own type of pattern which cannot match with anyone else.
Even identical twins have different fingerprints and unless the lower layer of the skin is damaged, this pattern stays the same throughout life. Fingerprints are a useful means of identifying people.
People often use fingerprints from the scene of a crime to nab a criminal. Newly born children in the hospital have their fingerprints done so that they do not get exchanged.