【单选题】Passage Two Questions 6 to 10 are based on the following passage。 Why do some people live to be older than others? You know the standard explanations: keeping a moderate diet, engaging in regular exer...
A.
to see whether people’s personality affects their life span
B.
to find out if one’s lifestyle has any effect on their health
C.
to investigate the role of exercise in living a long life
D.
to examine all the factors contributing to longevity