Although my father’s college mate

Although my father’s college mate may have changed over time due to climatic environmental changes as well as growth and development, some of human physical characteristics remain intact with age and are easily diagnosed.
Although his friend may have changed physical as well as emotionally due to age, the eye color of a human being remains the same throughout their lives. The look of his eye color in the yearbook 30 years ago will still be the same and hence it will be diagnostic (Wilson, 2012). Subsequently, his height will still remain constant as height in human beings is not volatile but a permanent change that occurs in human beings and cannot be changed or altered by anything. Although the beard would have changed in color over time, they would still posses the same look as they were thirty years ago (Wilson, 2012).
However, weight as a physical trait will not be that useful. This is because human beings are volatile to change in weight due to their eating habits, lifestyle, or their daily activities. This is the same case with the hair color (Waytz, Epley, & Cacioppo, 2010). Human hair color changes with age and so his hair color would not be the same as it was thirty years ago when he was still a college student and hence it will be ambiguous.
The voice of a person despite aging remains the same over time and hence it will determine to identify a person. Additionally, the eye and ear shape remains the time over time as they are not prone to change to due age or environmental conditions one may be exposed to (Wilson, 2012).

References
Waytz, A., Epley, N., & Cacioppo, J. T. (2010). Social Cognition Unbound Insights Into Anthropomorphism and Dehumanization. Current Directions in Psychological Science, 19(1), 58-62.
Wilson, E. O. (2012). On human nature. Harvard University Press.