What type of authentication method uses unique biological traits?

Biometrics refers to authentication methods that utilize unique biological traits for security verification. This could include fingerprints, facial recognition, iris scans, or voice recognition. The defining characteristic of biometrics is that it relies on the physical or behavioral characteristics of the user, which are inherently unique to every individual, making it difficult for unauthorized users to replicate.

Other authentication methods listed do not specifically involve biological traits. For instance, two-factor authentication generally involves a combination of two different factors, such as something you know (like a password) and something you have (like a smartphone). Multi-factor authentication expands this concept by involving more than two types of authentication factors, which can include knowledge factors, possession factors, and inherence factors, but does not exclusively focus on biological traits. Token-based authentication relies on a physical device (the token) to generate a code or serve as a key, significantly differing from biometrics.

Thus, biometrics stands out as the correct choice because it directly involves the use of physical characteristics for authenticating an individual's identity.