Throughout history man has had to
accept the fact that all living things must die, but people now live longer than
they (51) Yet, all living things still show the (52)
of aging, which will eventually (53)
death. Aging is not a disease, but as a person passes maturity, the cells of the body and the (54) they form do not function (55) they did in childhood and adolescence. The body provides less (56) against disease mad is more (57) accident. A number of related causes may (58) aging. Some cells of the body have a fairly long life, but they are not (59) when they, die. As a person ages, (60) of brain cells and muscle cells decreases. (61) body cells die and are replaced by new cells. In an aging person the (62) cells may not be as viable or as (63) A. brains B. brain C. heart D. organs 我来回答: 提交
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