Which biometric characteristic is known for remaining the same throughout a person's life?

The biometric characteristic recognized for being consistent throughout a person's life is the eye iris. The unique patterns and features of the iris remain stable after a certain age, which typically occurs in early childhood. This stability makes iris recognition a highly reliable method for biometric identification, as it is less affected by age-related changes, unlike other biometric traits.

For instance, while fingerprints are generally stable, they can be altered by injuries or wear. Voiceprints can change due to factors such as aging, health conditions, or emotional states. Similarly, facial features can change over time due to weight fluctuations, aging, and other physical alterations. In contrast, the iris's robustness and unique characteristics make it an extremely dependable option for long-term identity verification.