题目内容：
As the pace of life continues to increase, we are fast losing the art of relaxation. Once you are in the （67） of rushing through life, being on the go from morning till night, it is hard to （68） down. But relaxation is essential for a （69） mind and body.Stress is natural part of everyday life and there is no way to （70） it. In fact, it is not the bad thing it is often （71） to be. A certain amount of stress is vital to provide （72） and give purpose to life. It is only （73） the stress gets out of control that it can lead to （74） performance and ill health.
The amount of stress arsons can withstand depends very much （75） the individual. Some people are not afraid of stress, and （76） characters are obviously prime material for managerial responsibilities. Others lose （77） at the first signs of unusual difficulties. When （78） to stress, in whatever form, we react both chemically and （79） .
In fact we make choice between "flight and fight" and in more primitive days the choices made the difference （80） life and death. The crises we meet today are （81） to be so extreme, but however little the stress, it （82） the same response. It is when such a reaction lasts long, through continued （83） to stress, that health becomes （84） Such serious conditions as high blood pressure and heart diseases have （85） links with stress. Since we cannot （86） stress from our lives (it would be unwise to do so even if we could), we need to find ways to deal with it.
阅读以上文章，回答题请在（67）处填上最佳答案。 A．routine
B．habit
C．principle
D．rule
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