Final answer:
Weight is generally not used in biometrics, as it lacks the level of uniqueness and variability found in other human features such as fingerprints, voice tones, and retina patterns.
Step-by-step explanation:
The human feature that is generally not used in biometrics is d) weight.
Biometrics is the measurement and analysis of unique physical or behavioral characteristics for the purpose of identification or authentication. Fingerprints, voice tones, and retina patterns are commonly used in biometrics because they are unique to each individual and can be easily measured and analyzed. However, weight does not possess the same level of uniqueness and variability as these other features, making it less reliable for biometric identification.
The feature among the options listed that is generally not used in biometrics is d) weight. Biometric systems frequently utilize unique characteristics that are less likely to change over time and can be easily and quickly measured. While fingerprints, voice tones, and retina patterns fall under this category, weight can fluctuate significantly over time and is not unique to individuals, making it an unreliable measure for biometric identification.