[单项选择]

Aging is not a disease, but as a person passes maturity, the cells of the body and the (39) they form do not function as well as they (40) in childhood and adolescence (青春期). The body provides less (41) against disease and is more prone (42) accident.A number of related cause may (43) aging. Some cells of the body have a fairly long life, but they are not (44) when they die. As a person ages, (45) of brain cells and muscle cells decrease, (46) body cells die and are replaced by new cells. In an aging person the (47) cells may not be as viable (能生存的) or as capable (48) growth as those of a young person.Another (49) in aging may be changes within the cells (50) . Some of the protein chemicals in cells are known (51) with age and become less elastic. This is why the skin of old people wrinkles and (52) . This is also the reason old people (53) in height. There may be other more i
A. method 
B. procedure 
C. development 
D. process

Aging is not a disease, but as a person passes maturity, the cells of the body and the (39) they form do not function as well as they (40) in childhood and adolescence (青春期). The body provides less (41) against disease and is more prone (42) accident.A number of related cause may (43) aging. Some cells of the body have a fairly long life, but they are not (44) when they die. As a person ages, (45) of brain cells and muscle cells decrease, (46) body cells die and are replaced by new cells. In an aging person the (47) cells may not be as viable (能生存的) or as capable (48) growth as those of a young person.Another (49) in aging may be changes within the cells (50) . Some of the protein chemicals in cells are known (51) with age and become less elastic. This is why the skin of old people wrinkles and (52) . This is also the reason old people (53) in height. There may be other more i
A. arms 
B. feet 
C. heart 
D. organs

Hearts and kidneys: If one’s diseased, better keep a close eye on the other. Surprising new research shows kidney disease somehow speeds up heart disease well before it has ravaged the kidneys. And perhaps not so surprising, doctors have finally proven that heart disease can trigger kidney destruction, too.
The work, from two studies involving over 50,000 patients, promises to boost efforts to diagnose simmering kidney disease earlier. All it takes are urine and blood tests that cost less than $ 25, something proponents want to become as routine as cholesterol checks. "The average patient knows their cholesterol, " says Dr. Peter McCullough, preventive medicine chief at Michigan’s William Beaumont Hospital. "The average patient has no idea of their kidney function. "
Chronic kidney disease, or CKD, is a quiet epidemic: Many of the
A. To examine their patients’ heart function carefully.
B. To have their patients’ chests X-rayed regularly.
C. To select volunteers from their patients for a kidney screening.
D. To start rigorously checking out their patients’ kidneys.