A、They have better dietary habits. B、They bear fewer social responsibilities. C、They are born with a stronger ability to sociali

Ageing is a curious thing, and people’s desire to beat it and death has become an industry worth hundreds of billions of dollars. Despite the huge investment into research, ageing remains somewhat obscure, although there are certain things researchers do understand. They know that women tend to have longer life spans, living on average six years longer than men. No one is really certain of the reason for this, although the speculation centers around the idea that women are more capable of surviving or handling disease than men. For virtually every disease, the effects are greater on men than they are on women. Some suggest that women’s immune systems benefit from their tendency to prioritize and nurture social connections. But for me, this explanation is hardly convincing.
    Researchers also know to an extent what causes ageing. For 60 years, it was believed that cells would continue to divide forever. It was only uncovered in relatively recent times that older people’s cells divide a smaller number of times than younger people’s. Only cancer cells, in fact, are capable of dividing forever. Human cells have a limited reproductive ability. To an extent, we can postpone the eventual stop of cells’ dividing through nutrition, exercise, good sleep and even relaxation techniques, but we cannot stop the ageing process. And researchers are yet to answer the ultimate question of ageing: why does the body ultimately fall to pieces? In the opinion of some of the world’s best scientific minds on the subject, part of the reason we don’t yet have any answer is because many researchers are looking in the wrong direction. Many public health policymakers believe that the resolution of age-associated disease will tell us something fundamental about the ageing process, but, say some top scientists, "that’s completely erroneous." The point to win the diseases of childhood were eliminated, but this did not provide any insight into childhood development. In the same way, the idea that the resolution of age-associated diseases like heart disease and stroke will inform us about ageing is not based on sound science or logic. At best, if the major causes of death in developed countries were eliminated, this would only add a decade to average life expectancy. But while there is money available to be spent on it, the search to understand the secrets of ageing will be ongoing.
    Questions 19 to 21 are based on the recording you have just heard.
    19. What do we learn about the possible reason why women tend to live longer?
    20. What is the recent discovery about human cells?
    21. What do many public health policymakers believe?