1. Which of the following phrases best describes a central idea of the article?
A. Many people do not have a firm understanding of how old they actually are.
B. The most common measurement of age is not very useful, and there are more
useful measures that exist.
C.
Biological and social age are arbitrary measures that do not reveal much about
one's true age.
D. Even though scientists have revealed that a healthy lifestyle can counteract
aging, many people still believe that their memory gets worse as they age.