______doesn't contribute to the remarkable long life of these people.

A．an example of a typical long lived people with a lot of hard physical work
B．an example of long lived people with remarkable memory
C．an explanation of why he is still healthy
D．an explanation of what way of life we should take

A．many people can live up to more than 100 years
B．many old people live very lonely
C．many people from other mountainous region come to settle here
D．many older persons become weak and ill in their 60s and 70s for no reason