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若按演替进程时间的长短划分,演替可分为哪几类?
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下列演替类型中不属于按演替进程时间长短分类的是( )
简述偏利共生和互利共生,并举例说明。
白蚁肠道内的鞭毛虫与白蚁是一种寄生关系。( )
土壤有机质包括非腐殖质和__________两大类。
对植物群体的总光能利用率产生影响的主要因素是光合面积、__________和光合能力。
在个体水平上,生态系统的稳态机制主要通过生理的和__________变化去适应环境的变化。
低温对生物的伤害分为冷害和__________两种。
环境按性质可分为自然环境、__________和社会环境。
捕食者和猎物相互作用的结果是协同进化。( )
生活型相同的植物对环境有相似的适应特征。( )
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关联方交易的披露应当遵循重要性的会计信息质量要求,判断关联方交易是否重要的依据是( ) 。
2.
7.自我开放属于心理辅导的操作技术中的
3.
试述跨国公司的薪酬战略目标主要包括?]
4.
3.Friction is a force which opposes motion. Much of the energy supplied to a complicated machine with many moving parts is wasted in overcoming this opposition. The energy is converted into useless heat. The amount thus lost can be considerably reduced and the life of the machine prolonged by careful lubrication. This reduction improves the efficiency of the machine. Another way in which friction is reduced is to substitute roller or ball bearings for the earlier type of bearing, in which the surfaces in contact move by sliding. Bearings of these later types are used very extensively in many kinds of modern machinery.It must not be assumed, however, that friction is always a disadvantage. In many instances it is highly important. Belts are often used in conveying power from one machine to another. In the absence of friction, this could not be done. The driving wheel would not run the belt, neither would the belt run the wheel to driver. Without friction, then, belted machinery could not be used. Again in the case of all motor vehicles, friction is essential in the operation of the brake. Were there no friction, there could be no brake. But even this illustration does not give an adequate picture of the importance of friction. The vehicle could not even be started if it were not for the friction exerted between the tires and the road. Nails hold in wood, and screws hold in either wood or metal by reason of friction, without which they would be useless. Walking is difficult enough on an icy pavement, but it would be wholly impossible if there were no friction at all between the shoe and the pavement.(5分)3.1Friction arises when____.(1分)A. an opposing force of motion existsB. the energy is wastedC. everything is motionlessD. a complicated machine is supplied with energy
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四、简答题:本大题共5小题,每小题6分,共30分
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