Question

Since there is no single biological benchmark that signals a person's becoming "old," ______ commonly serves as the proxy measure for predicting health status and functional abilities.

Answer 1

chronological age

Step-by-step explanation:

People's biological age or the physiological age are the signs and symptoms which shows how old people have grown. They are sign that shows ageing in people. However biological age can be lower by exercising, avoid taking stress, taking good healthy diet and maintaining good lifestyle.

While, chronological age is the measure of the years that an individual is alive. it is based on calendar date from the date people are born.

Thus there is no biological benchmark which shows people are becoming 'old' and chronological age is used as a proxy measure to predict health status and body functions.

Hence the answer is --

chronological age