"Iris scan  , please," the bank's computer voice tells you . You step up and the computer reads your eye , comparing it to the stored file it has of your iris. The images had better match--otherwise you won't be able to get your money. Iris scanning and other technologies , such as fingerprint and voice scanning , have appeared in many science fiction movies in the past. Today , these advanced technologies are part of the real world. They are common at work, the bank, the airport, and your local prison. The iris scan, fingerprint scan, and voice scan are all examples of biometrics  a fast developing area of automatic personal identification technology . Basically , biometrics uses various ways to verify a persons identity , based on the individual's unique characteristics ,including fingerprints , voices, irises, body heat patterns, facial images, handprints , signatures and so on. Biometrics identification systems have a number of advantages over password systems. The primary advantage is that an individual has to be physically present in order to be identified. Another important advantage is that there are no passwords to remember , forget, lose or steal. The voice scan is the simplest and most affordable form of biometrics . It only requires a computer, a microphone and the correct software. The software records a subject's voice and then compares it to a stored voice sample for identification purposes. For additional safety, fingerprint and handprint scans can also be employed . Fingerprint scans take the image of a fingerprint and compare it to a stored file of prints. Handprint scans identify the unique features of a hand. Iris scans currently give the highest level of accuracy among all the available biometrics systems. Another technology , full facial scans , is currently in use at border crossings and airports. Facial scanning equipment can actually track and identify moving faces within a crowd. The potential of biometrics is exciting and encouraging . With continued development , testing , and application , current technologies will become even more effective in the future. Soon , the days of password and car keys will be gone . Just don't leave home without your fingerprints! Which is the most accurate form of biometrics?
The voice scan The fingerprint scan The iris scan The facial scan