65 résultats pour "producing"
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Nuclear Energy
I
INTRODUCTION
Gundremmingen Nuclear Power Plant, Germany
The first of three boiling-water nuclear reactors at Germany's Gundremmingen plant began operating in 1966 but was
permanently shut down after being decommissioned in 1983.
such as ¯U is induced by the absorption of a neutron as in producing cesium-140, rubidium-93, three neutrons, and 200 MeV, or 3.2 × 10 -11 J (7.7 × 10 -12 cal). A nuclear fission reaction releases 10 million times as much energy as is released in a typical chemical reaction. See Nuclear Chemistry. III NUCLEAR ENERGY FROM FISSION The two key characteristics of nuclear fission important for the practical release of nuclear energy are both evident in equation (2). First, the energy per fiss...
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Diabetes Mellitus.
Once diabetes is diagnosed, treatment consists of controlling the amount of glucose in the blood and preventing complications. Depending on the type of diabetes, thiscan be accomplished through regular physical exercise, a carefully controlled diet, and medication. Individuals with Type 1 diabetes must receive insulin, often two to four times a day, to provide the body with the hormone it does not produce. Insulin cannot be takenorally, because it is destroyed in the digestive system. Consequent...
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Genetic Engineering.
Pseudomonas fluorescens bacterium. The genetically altered Pseudomonas fluorescens bacterium produces light in proportion to the amount of its activity in breaking down the naphthalene, thus providing a way to monitor the efficiency of the process ( see Bioremediation). A3 Medicine In 1982 the United States Food and Drug Administration (FDA) approved for the first time the medical use of a recombinant DNA protein, the hormone insulin, whichhad been cloned in large quantities by inserting th...
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Prokaryote - biology.
earliest organisms to evolve, an estimated 3.4 billion to 3.5 billion years ago. The environment of the early Earth lacked oxygen, and cyanobacteria probably usedfermentation (a chemical process performed without the presence of oxygen) to produce the energy molecule adenosine triphosphate (ATP). Cyanobacteria introduced oxygen into the atmosphere through the process of photosynthesis. As the oxygen content in the atmosphere increased over the centuries, bacteria evolved that usedthis oxygen in...
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Ant - biology.
The workers of many ant species carry a stinger within the hind end of the gaster. These ants use the stinger to defend against their enemies. In some species, workerants lack a stinger but use the tip of their gaster to squirt or dab poison at other small animals and when fighting battles with other ants, fending off predators, or killinginsects or other animals that they use as food. III PHYSIOLOGY Ants have a rigid, external skeleton called an exoskeleton that gives the soft, inner body its...
- A member of the European Union, the Netherlands are the leading country for producing and exporting natural gas in Europe.
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Nuclear Weapons.
Regardless of the method used to attain a supercritical assembly, the chain reaction proceeds for about a millionth of a second, liberating vast amounts of heat energy.The extremely fast release of a very large amount of energy in a relatively small volume causes the temperature to rise to tens of millions of degrees. The resultingrapid expansion and vaporization of the bomb material causes a powerful explosion. VI PRODUCTION OF FISSILE MATERIAL Much experimentation was necessary to make the p...
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British Empire .
B1 The Seven Years’ War During the Seven Years’ War in Europe (1756-1763), Britain made large imperial gains at the expense of France. The North American segment of the Seven Years’ Warwas known as the French and Indian War. It was launched by the British against French possessions in North America in 1754, and in 1758 the British captured theFrench fortress of Louisbourg, which gave them access to French territory in the St. Lawrence Valley. In the following year Québec was captured, marking t...
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American Westward Movement - U.
British expansion. However, Native Americans of the Great Lakes and Ohio Valley lashed out against the English in an attempt to preserve their independence, theirland, and their way of life. With the Ottawa chief Pontiac as their most visible leader, the tribes waged a bloody and costly war. As a result, the British governmentdecided to keep the white settlers apart from the Native Americans. It issued the Royal Proclamation of 1763, banning all white settlement beyond the Appalachians andstatin...
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Advertising.
Advertising agencies make money in a variety of ways. When the agency uses the client’s advertising budget to buy time for an ad on the radio or on television or whenit buys space for an ad in a newspaper or magazine, the media outlet allows the agency to keep 15 percent of the cost of the space or the time as a commission. The15 percent commission has become an advertising industry standard and usually accounts for the largest portion of the agency’s income. Agencies also charge clientsfor the...
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Meteorology.
to find the corresponding relative humidity and dew-point temperature. III SPECIAL METEOROLOGICAL INSTRUMENTS Meteorologists have developed several sophisticated instruments that measure multiple physical characteristics of the air simultaneously and at more than one location.The most important of these special instruments are radiosondes, Doppler radar, and weather satellites. A Radiosonde A radiosonde measures air temperature, air pressure, and humidity from the earth’s surface up to an alt...
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Physics
I
INTRODUCTION
Physics, major science, dealing with the fundamental constituents of the universe, the forces they exert on one another, and the results produced by these forces.
Starting about 1665, at the age of 23, Newton enunciated the principles of mechanics, formulated the law of universal gravitation, separated white light into colors,proposed a theory for the propagation of light, and invented differential and integral calculus. Newton's contributions covered an enormous range of naturalphenomena: He was thus able to show that not only Kepler's laws of planetary motion but also Galileo's discoveries of falling bodies follow a combination of his ownsecond law of m...
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Parkinson Disease.
III SYMPTOMS Parkinson disease most notably affects motor control (muscle activity). The disease progresses differently for each individual—symptoms develop swiftly in some peopleand slowly in others. Some Parkinson patients may develop problems that affect their intellect or ability to reason, or they may suffer from depression or anxiety. A Motor Control Problems Doctors look for the presence of four principal symptoms in patients they suspect may have Parkinson disease. Tremor (the involun...
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Culture.
form of knowledge, such as scientific discoveries; objects, such as works of art; and traditions, such as the observance of holidays. C1 Ethnocentrism and Cultural Relativism Self-identity usually depends on culture to such a great extent that immersion in a very different culture—with which a person does not share common ways of life orbeliefs—can cause a feeling of confusion and disorientation. Anthropologists refer to this phenomenon as culture shock. In multicultural societies —societies s...
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Beetle - biology.
cut, or crush prey. Beetles that consume nectar from flowers use tubelike mouthparts to suck up nectar like a primitive straw. C Thorax The thorax, the body region behind the head, consists of three segments that provide attachments for the legs and wings. Each segment of the thorax carries a pair oflegs. The middle segment also bears the stiff wing sheaths called elytra, and the hind segment holds the membranous hind wings. D Legs Beetles have six jointed legs, each leg with five parts. The f...
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Iowa - geography.
Okoboji, Lost Island, Silver, and West Swan lakes. In addition, reservoirs have been created by damming several smaller Iowa rivers. There are a number of largereservoirs behind dams on the Mississippi River along the Iowa state line. C Climate Iowa’s climate is characterized by warm, generally moist summers and cold winters. Temperatures vary considerably from season to season and, at times, from day today. However, monthly averages are relatively uniform throughout the state and usually vary...
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Iowa - USA History.
Okoboji, Lost Island, Silver, and West Swan lakes. In addition, reservoirs have been created by damming several smaller Iowa rivers. There are a number of largereservoirs behind dams on the Mississippi River along the Iowa state line. C Climate Iowa’s climate is characterized by warm, generally moist summers and cold winters. Temperatures vary considerably from season to season and, at times, from day today. However, monthly averages are relatively uniform throughout the state and usually vary...
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Illinois - geography.
the state before joining the Mississippi River at Grafton. The Illinois has been deepened and straightened and forms part of the Illinois Waterway. The watershed between rivers that flow into the Mississippi river system and rivers that flow into the Great Lakes is low and in many places is not easily discernible. Inwhat is now the Chicago area, explorers had little difficulty portaging, or carrying, their canoes over the low watershed between the Des Plaines River, which flows intothe Illinois,...
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Illinois - USA History.
the state before joining the Mississippi River at Grafton. The Illinois has been deepened and straightened and forms part of the Illinois Waterway. The watershed between rivers that flow into the Mississippi river system and rivers that flow into the Great Lakes is low and in many places is not easily discernible. Inwhat is now the Chicago area, explorers had little difficulty portaging, or carrying, their canoes over the low watershed between the Des Plaines River, which flows intothe Illinois,...
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Walt Disney
I
INTRODUCTION
Walt Disney
Walt Disney, an American cartoonist and film producer, started an entertainment empire with his creation of animated
movies and world-renowned amusement parks.
Donald DuckDonald Duck waves to visitors at Walt Disney World in Orlando, Florida. The Disney Studios created the excitable duck in1934.Kelly-Mooney Photography/Corbis In 1923 Disney moved to Hollywood, California. He, his brother Roy O. Disney, and Iwerks began producing short animated films. In 1927 Disney created the cartooncharacter Oswald the Rabbit. A year later he produced another character, a mouse called Mortimer, but shortly after changed the name to Mickey. In 1928 MickeyMouse starred...
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Sheep - biology.
fine-wool or crossbred ewes, they are bred to rams of the Down breeds for the production of lambs for meat. The bands may be moved from place to place to takeadvantage of cheap feeds and natural forage. Similar operations are used on lands with developed pastures. If abundant forage is available, the lambs may bemarketed directly after weaning. If the lambs have not reached marketable condition, they may be moved to feedlots and given additional food before they are sold. Some breeders specializ...
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Water - chemistry.
flourides in drinking water has been found to reduce tooth decay. See Fluorine. Seawater contains, in addition to concentrated amounts of sodium chloride, or salt, many other soluble compounds, as the impure waters of rivers and streams areconstantly feeding the oceans. At the same time, pure water is continually lost by the process of evaporation, and as a result the proportion of the impurities that givethe oceans their saline character is increased. See Ocean and Oceanography. VII WATER...
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Artificial Intelligence.
Work in AI has primarily focused on two broad areas: developing logic-based systems that perform common-sense and expert reasoning, and using cognitive andbiological models to simulate and explain the information-processing capabilities of the human brain. In general, work in AI can be categorized within three research anddevelopment types: symbolic, connectionist, and evolutionary. Each has characteristic strengths and weaknesses. A Symbolic AI Symbolic AI is based in logic. It uses sequences...
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Yangtze - Geography.
A Agriculture and Industry Today about 400 million people, or about one-third of the population of China, live in the Yangtze Basin. Many are engaged in agriculture. The basin contributes nearlyhalf of China’s crop production, although only one-quarter of the basin is arable. The most fertile areas for farming are the Sichuan Basin, the plains between theYangtze and its tributary the Han, and the plains of the lower basin. In all about 40 percent of the cereals, more than 30 percent of the cott...
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Immune System.
The humoral immune response involves a complex series of events after antigens enter the body. First, macrophages take up some of the antigen and attach it to classII MHC molecules, which then present the antigen to T helper cells. The T helper cells bind the presented antigen, which stimulates the T helper cells to divide andsecrete stimulatory molecules called interleukins. The interleukins in turn activate any B lymphocytes that have also bound the antigen. The activated B cells then divide...
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Poliomyelitis.
Physical therapy helps patients with paralytic polio stretch and move affected muscles. This movement minimizes the atrophy, or shrinkage, of affected muscles andlimbs and builds strength. Exercises can also retrain working muscles to compensate for other muscles that have permanently lost the ability to move. Rehabilitativetherapy trains patients to use braces, crutches, and other devices that provide support and aid mobility. V PREVENTION OF POLIO Immunization with polio vaccine is the best w...
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Capitalism.
Physiocracy is the term applied to a school of economic thought that suggested the existence of a natural order in economics, one that does not require direction from the state for people to be prosperous. The leader of the physiocrats, the economist François Quesnay, set forth the basic principles in his Tableau économique (1758), in which he traced the flow of money and goods through the economy. Simply put, this flow was seen to be both circular and self-sustaining. More important, however...
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Fungus - biology.
Many fungi can reproduce by the fragmentation of their hyphae. Each fragment develops into a new individual. Yeast, a small, single-celled fungus, reproduces bybudding, in which a bump forms on the yeast cell, eventually partitioning from the cell and growing into a new yeast cell. V CLASSIFICATION OF FUNGI Scientists have long disagreed about how to classify fungi, and the classification systems are still developing. The first description of fungi was published in 1729 byItalian botanist Pier...
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Spider (arthropod) - biology.
The spider’s abdomen is soft and saclike. On the underside of the tip of the abdomen are three pairs of spinnerets. Each spinneret is studded with many fine, hairliketubes called spigots, which produce a variety of silk threads. The spigots lead to several large silk glands inside the abdomen. Silk is formed as a liquid inside theseabdominal glands. As the silk is drawn out through the spigots, protein molecules within the silk line up parallel to one another, causing the silk to harden and form...
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Inca Empire.
The Incas’ public works were built through a labor tax known as mit’a. This tax required most people incorporated into the Inca Empire to provide labor for public worksduring certain portions of each year. This labor tax supported large-scale public works that required the marshalling of large labor forces, such as for the building offorts, roads, and bridges, or the mining of metals and gems. It also allowed the emperor to raise large armies to undertake wars of conquest. Road building was impo...
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Inca Empire - History.
The Incas’ public works were built through a labor tax known as mit’a. This tax required most people incorporated into the Inca Empire to provide labor for public worksduring certain portions of each year. This labor tax supported large-scale public works that required the marshalling of large labor forces, such as for the building offorts, roads, and bridges, or the mining of metals and gems. It also allowed the emperor to raise large armies to undertake wars of conquest. Road building was impo...
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Nanotechnology.
ever-finer method of reducing material to the nanoscale size. Instead, nanostructures would be assembled atom by atom and molecule by molecule, from the atomiclevel up, just as occurs in nature. However, assembly at this scale has its own challenges. In school, children learn about some of these challenges when they study the random Brownian motion seen in particles suspended in liquids such as water. Theparticles themselves are not moving. Rather, the water molecules that surround the particles...
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Heart.
situation. A Cardiac Cycle Although the right and left halves of the heart are separate, they both contract in unison, producing a single heartbeat. The sequence of events from the beginning ofone heartbeat to the beginning of the next is called the cardiac cycle. The cardiac cycle has two phases: diastole, when the heart’s chambers are relaxed, and systole,when the chambers contract to move blood. During the systolic phase, the atria contract first, followed by contraction of the ventricles. T...
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Cloning - biology.
found that such embryo cells are totipotent (able to give rise to all the different cell types in the body). Exploiting this characteristic, scientists developed three techniques to clone embryo cells: blastomere separation, blastocyst division, and somatic cell nuclear transfer. A Blastomere Separation In blastomere separation, scientists fertilize an egg cell with a sperm cell in a laboratory dish. The resulting embryo is allowed to divide until it forms a mass of aboutfour cells. Scientist...
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Globalization.
higher living standard for their people. The World Bank made loans to developing countries for dams and other electrical-generating plants, harbor facilities, and otherlarge projects. These projects were intended to lower costs for private businesses and to attract investors. Beginning in 1968 the World Bank focused on low-cost loansfor health, education, and other basic needs of the world’s poor. B International Monetary Fund The IMF makes loans so that countries can maintain the value of thei...
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San Francisco - geography.
recognized symbol of the city, opened in 1937. It connects San Francisco to Marin County to the north, one of the wealthiest suburban areas in the nation. With the construction of the Bay and Golden Gate bridges and other links from the city to its suburbs, the San Francisco Bay area has become one large metropolitanregion. San Francisco itself is only 122 sq km (47 sq mi) of land area, but the city’s Primary Metropolitan Statistical Area (defined by the Census Bureau as SanFrancisco, San Mateo,...
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Mississippi - geography.
The climate of Mississippi is characterized by long, hot, and humid summers and generally mild winters. The higher lands in the northeast are usually cooler than otherareas of the state. D1 Temperature Average January temperatures range from about 6° C (about 42° F) in northeastern Mississippi to about 12° C (about 54° F) along the Gulf Coast. No part of the stateis entirely free from freezing temperatures, but prolonged periods of extreme cold rarely occur. Temperatures more than 15° C (30° F)...
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Mississippi - USA History.
The climate of Mississippi is characterized by long, hot, and humid summers and generally mild winters. The higher lands in the northeast are usually cooler than otherareas of the state. D1 Temperature Average January temperatures range from about 6° C (about 42° F) in northeastern Mississippi to about 12° C (about 54° F) along the Gulf Coast. No part of the stateis entirely free from freezing temperatures, but prolonged periods of extreme cold rarely occur. Temperatures more than 15° C (30° F)...
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New Jersey - geography.
C Soils Broadly defined, all of New Jersey’s soils are podzolic soils; that is, they are acidic and contain fairly high amounts of iron oxides. The soils in northern New Jersey areirregular in quality and contain rock fragments and small stones deposited by the continental glaciers of the last Ice Age. The soils of the inner coastal plain, unaffectedby glaciation, are the richest in the state, while those of the outer coastal plain are generally infertile. The newer soil classification system d...
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New Jersey - USA History.
C Soils Broadly defined, all of New Jersey’s soils are podzolic soils; that is, they are acidic and contain fairly high amounts of iron oxides. The soils in northern New Jersey areirregular in quality and contain rock fragments and small stones deposited by the continental glaciers of the last Ice Age. The soils of the inner coastal plain, unaffectedby glaciation, are the richest in the state, while those of the outer coastal plain are generally infertile. The newer soil classification system d...
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India - country.
delta in the north, are intensely farmed. B Rivers and Lakes The rivers of India can be divided into three groups: the great Himalayan rivers of the north, the westward-flowing rivers of central India, and the eastward-flowingrivers of the Deccan Plateau and the rest of peninsular India. Only small portions of India’s rivers are navigable because of silting and the wide seasonal variation inwater flow (due to the monsoon climate). Water transport is thus of little importance in India. Barrages,...
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Photosynthesis - biology.
P680 in Photosystem II is now electron deficient because it has donated electrons to P700 in Photosystem I. P680 electrons are replenished by the water that has beenabsorbed by the plant roots and transported to the chloroplasts in the leaves. The movement of electrons in Photosystems I and II and the action of an enzyme split thewater into oxygen, hydrogen ions, and electrons. The electrons from water flow to Photosystem II, replacing the electrons lost by P680. Some of the hydrogen ions maybe...
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Business.
The most common form of ownership is a sole proprietorship —that is, a business owned by one individual. At the beginning of the 21st century, there were more than 17 million sole proprietorships in the United States. These businesses have the advantage of being easy to set up and to dissolve because few laws exist to regulatethem. Proprietors, as owners, also maintain direct control of their businesses and own all their profits. On the other hand, owners of proprietorships are personallyrespon...
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Helicopter.
naturally flaps down so as to increase lift. Flapping allows the differences in lift caused by uneven rotor tip speed to cancel out, producing a stable ride. Many helicoptersuse mechanical hinges with lubricated bearings, but some use flexible straps made of a composite material in order to reduce the required maintenance. Helicopters require different amounts of lift and thrust at different times during flight, because the aerodynamic forces acting on them change during hovering andacceleration...
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Thomas Edison.
While Edison was working on the electric light, he made a scientific discovery that would become important to future generations. Edison noticed that particles of carbonfrom the filament blackened the insides of his light bulbs. This effect was caused by the emission of electrons from the filament, although Edison made the discoverybefore he and other scientists knew the electron existed. Not until 1897 did British physicist J. J. Thomson prove that the blackening observed by Edison was caused b...
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Thomas Edison - USA History.
While Edison was working on the electric light, he made a scientific discovery that would become important to future generations. Edison noticed that particles of carbonfrom the filament blackened the insides of his light bulbs. This effect was caused by the emission of electrons from the filament, although Edison made the discoverybefore he and other scientists knew the electron existed. Not until 1897 did British physicist J. J. Thomson prove that the blackening observed by Edison was caused b...
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Sewage Disposal.
greater load on the piping system and the treatment plant. The amount of storm-water drainage to be carried away depends on the amount of rainfall as well as on the runoff or yield of the watershed ( see Drainage). A typical metropolitan area discharges a volume of wastewater equal to about 60 to 80 percent of its total daily water requirements, the rest being used for washingcars and watering lawns, and for manufacturing processes such as food canning and bottling. B Composition The composi...
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Slavery in Africa.
The spread of Islam from Arabia into Africa after the religion’s founding in the 7th century AD affected the practice of slavery and slave trading in West, Central, and East Africa. Arabs had practiced slave raiding and trading in Arabia for centuries prior to the founding of Islam, and slavery became a component of Islamic traditions.Both the Qur'an (Koran) (the sacred scripture of Islam) and Islamic religious law served to codify and justify the existence of slavery. As Muslim Arabs conquered...
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Hydrogen - chemistry.
Hydrogen gas does not usually react with other chemicals at room temperature. That is, it does not split into two hydrogen atoms to combine with other chemicals. Thebond between the hydrogen atoms is very strong and can only be broken with a large amount of energy. However, when heated with a flame or a spark, hydrogen gaswill react violently with oxygen in the air to produce water in the following reaction: 2H2 + O 2 → 2H 2O This chemical equation shows that two hydrogen molecules (H 2) and o...
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Heredity - biology.
allele from the mother and a mutated allele from the father. In both of these cases, the child will be a carrier. The child develops the disease only if he or she receives amutated allele from each parent. When both parents are carriers, there is a 25 percent chance that a child will be disease-free, a 25 percent chance that it will have thedisease, and a 50 percent chance that it will be a carrier. Examples of genetic diseases that follow the dominant-recessive pattern include sickle-cell anemi...