Which multi-factor authentication method utilizes unique physical characteristics of individuals?

Biometrics is the multi-factor authentication method that utilizes unique physical characteristics of individuals, making it a highly secure form of identity verification. This method leverages traits such as fingerprints, facial recognition, iris patterns, or other identifiable human features to authenticate a user. The inherent uniqueness of these physical attributes means that they cannot be easily replicated or stolen, providing a robust layer of security.

In contrast, other methods do not rely on these identifiable traits. Password-based authentication requires users to remember and input a secret password, which can be forgotten or compromised. Token-based authentication involves the use of a physical device or software token to generate a code, which also does not include physical characteristics. Knowledge-based authentication requires users to provide information that they know, such as answers to security questions, which may be vulnerable to social engineering attacks. Thus, these other methods do not offer the same level of security that biometrics provides by leveraging unique and unforgeable attributes.