力是指（）
A.在正常咀嚼运动中，咀嚼食物的力大约只为牙周组织所能支持的力量的一半，而在牙周组织中储存了另一半的支持能力
B.牙周膜面积
C.在实际咀嚼运动中，只有部分肌纤维参与了收缩运动产生的力量
D.在咀嚼运动中，咀嚼肌收缩时所能发挥的最大力量
E.力的一部分
参考答案：C
解析：
1.咀嚼力是咀嚼肌收缩时所能发挥的最大力量，比咀嚼压力大。2.在实际咀嚼运动中，咀嚼力受到牙周组织内痛觉感觉器的调控，只有部分肌纤维参与了收缩运动，形成咀嚼压力。咀嚼压力是咀嚼力的一部分。3.
力即咀嚼压力，是咀嚼力的一部分。4.牙周潜力又称牙周储备力，是牙周组织中储存的支持能力。
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| 1 today's world, almost everyone knows that air pollution 2 people's health. However, 3 people know that noise is also a kind of pollution and does harm to humans' health. People who work and live in 4 coditions go deaf easily. For example, many of the workers 5 print newspapers and books go deaf. Quite a few people 6 near airports also have hearing loss. Recently, 7 that many teenagers in America can hear 8 65-year-old people do, 9 these young people always listen to loud pop music. 10 a loud noise in public is also a kind of pollution. It not only 11 others but also does great harm to people's hearing. Cars and machines also produce 12 noise. Such pollution makes people 13 uncomfortable and unpleasant, and it can even cause them 14 sick or deaf. Nowadays, many countries are trying to solve 15 environmental problems, including noise pollution. | ||||
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