Cells cannot remain alive outside certain limits of temperature and much narrower limits mark the boundaries of effective functioning. Enzyme systems of mammals and birds are most efficient only within a narrow range around 37C;a departure of a few

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16. the war between Britain and France In the late eighteenth century, battles raged in almost every corner of Europe, as well as in the Middle East, south Africa ,the West Indies, and Latin America. In reality, however, there was only one major war

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02 Schooling and Education It is commonly believed in United States that school is where people go to get an education. Nevertheless, it has been said that today children interrupt their education to go to school. The distinction between schooling a

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Andrew Carnegie, known as the King of Steel, built the steel industry in the United States, and , in the process, became one of the wealthiest men in America. His success resulted in part from his ability to sell the product and in part from his pol

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03 The Definition of Price Prices determine how resources are to be used. They are also the means by which products and services that are in limited supply are rationed among buyers. The price system of the United States is a complex network compose

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Standard usage includes those words and expressions understood, used, and accepted by a majority of the speakers of a language in any situation regardless of the level of formality. As such, these words and expressions are well defined and listed in

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Bacteria are extremely small living things. While we measure our own sizes in inches or centimeters, bacterial size is measured in microns. One micron is a thousandth of a millimeter: a pinhead is about a millimeter across. Rod-shaped bacteria are u

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A folk culture is a small isolated, cohesive, conservative, nearly self-sufficient group that is homogeneous in custom and race with a strong family or clan structure and highly developed rituals. Order is maintained through sanctions based in the r

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If the salinity of ocean waters is analyzed, it is found to vary only slightly from place to place. Nevertheless, some of these small changes are important. There are three basic processes that cause a change in oceanic salinity. One of these is the

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19 childrens numerical skills people appear to born to compute. The numerical skills of children develop so early and so inexorably that it is easy to imagine an internal clock of mathematical maturity guiding their growth. Not long after learning t

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21 The Origin of Sports When did sport begin? If sport is, in essence, play, the claim might be made that sport is much older than humankind, for , as we all have observed, the beasts play. Dogs and cats wrestle and play ball games. Fishes and birds

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20 The Historical Significance of American Revolution The ways of history are so intricate and the motivations of human actions so complex that it is always hazardous to attempt to represent events covering a number of years, a multiplicity of perso

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29 Telecommuting Telecommuting-- substituting the computer for the trip to the job ----has been hailed as a solution to all kinds of problems related to office work. For workers it promises freedom from the office, less time wasted in traffic, and h

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33 Plankton浮游生物. Scattered through the seas of the world are billions of tons of small plants and animals called plankton. Most of these plants and animals are too small for the human eye to see. They drift about lazily with the currents, provid

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27. Scientific Theories In science, a theory is a reasonable explanation of observed events that are related. A theory often involves an imaginary model that helps scientists picture the way an observed event could be produced. A good example of thi

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31 British Columbia British Columbia is the third largest Canadian provinces, both in area and population. It is nearly 1.5 times as large as Texas, and extends 800 miles(1,280km) north from the United States border. It includes Canadas entire west

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34 Raising Oysters In the oysters were raised in much the same way as dirt farmers raised tomatoes- by transplanting them. First, farmers selected the oyster bed, cleared the bottom of old shells and other debris, then scattered clean shells about.

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An important new industry, oil refining, grew after the Civil war. Crude oil, or petroleum a dark, thick ooze from the earth had been known for hundreds of years, but little use had ever been made of it. In the 1850s Samuel M. Kier, a manufacturer i

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The theory of plate tectonics describes the motions of the lithosphere, the comparatively rigid outer layer of the Earth that includes all the crust and part of the underlying mantle. The lithosphere(n.[地]岩石圈)is divided into a few dozen plates o

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Since its first appearance in the 15th century in the courts of European royalty, ballet has become one of the most loved forms of dance. One of the most beloved ballets is Swan Lake. First performed in Russia in 1895, it continues to thrill audience

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