[单项选择]At the age of twelve years, the human body is at its most vigorous. It has yet to reach its full size and strength, and its owner his or her full intelligence; but at this age the likelihood of death is least. Earlier, we were infants and young children, and consequently more vulnerable; later, we shall undergo a progressive loss of our vigor and resistance which, though imperceptible at first, will finally become so steep that we can live no longer, however well we look after ourselves, and however well society, and our doctors, look after us.
This decline in vigor with the passing of time is called ageing. It is one of the most unpleasant discoveries which we all make that we must decline in this way, that if we escape wars, accidents and disease we shall eventually "die of old age", and that this happens at a rate which differs little from person to person, so that there are heavy odds in favor of our dying between the ages of sixty-five and eighty. Some of us will die soone
A. Normally people are quite familiar with the ageing process.
B. All animals and other organisms undergo the ageing process.
C. The law of thermodynamics functions in the ageing process.
D. Human’s ageing process is different from that of mechanisms.