1588 résultats pour "years"
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Hippopotamus - biology.
hippo backs up to its droppings and uses its tail as a paddle, flicking the dung through the air. This creates a pile that can become several meters wide over time. Male river hippos start to establish territories when they are in their early 20s, and they may eventually control more than 250 m (820 ft) of the water's edge.Subordinate males come and go freely, but a rival male will spark a confrontation if it tries to intrude. The territory owner and intruder face each other open-mouthedand, if...
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Benjamin Franklin.
Copley Medal for distinguished contributions to experimental science. Franklin also exerted a great influence on education in Pennsylvania. In 1749 he wrote thepamphlet Proposals Relating to the Education of Youth in Pennsylvania; its publication led to the establishment in 1751 of the Academy of Philadelphia, later to become the University of Pennsylvania. The curriculum he suggested departed considerably from the study of the Greek and Roman classics then in vogue. Instead itemphasized Engl...
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Benjamin Franklin - USA History.
Copley Medal for distinguished contributions to experimental science. Franklin also exerted a great influence on education in Pennsylvania. In 1749 he wrote thepamphlet Proposals Relating to the Education of Youth in Pennsylvania; its publication led to the establishment in 1751 of the Academy of Philadelphia, later to become the University of Pennsylvania. The curriculum he suggested departed considerably from the study of the Greek and Roman classics then in vogue. Instead itemphasized Engl...
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Tuberculosis.
TB has existed for thousands of years. Scars on a skull found in Turkey indicate the presence of the disease 500,000 years ago. Scientists also have found tubercles inmummified bodies from ancient Egypt. References to TB can be found in the writings of ancient Babylonia, Egypt, and China. The term tuberculosis was first used in 1839; it was derived from the Latin word tubercula, meaning small lump, referring to the small scars seen in tissues of infected individuals. TB reappeared in Europe...
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Toys.
I
INTRODUCTION
Toys, objects that serve as playthings for children. Although the
clay. These readily available elements were also used to make more elaborate toys as human society advanced. Archaeologists have found primitive, handmade toys such as wooden or cloth dolls, clay marbles, and terracotta figures that date back thousands of years. In ancientEgypt, Greece, and Rome, people placed dolls or clay figures in the graves or tombs of children for them to play with in the afterlife. The yo-yo may seem like a 20th-century fad, but it actually dates back at least 2,500 years...
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Badminton.
Once play has started, players tend to hit straight, low-flying shots called drives. When the shuttle remains close to the center of the court, net shots can be a goodoption. Net shots can be hard-hit or delicate. They are aimed at the front area of the opponent’s court, forcing the opponent to play the shot close to the net. If the opponent manages to return a net shot, the return must be hit high to clear the net. This gives the player a chance for a smash—the deadliest attacking stroke inbadm...
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Plate Tectonics.
ridges. The Mid-Atlantic Ridge is an underwater mountain range created at a divergent plate boundary in the middle of the Atlantic Ocean. It is part of a worldwidesystem of ridges made by seafloor spreading. The Mid-Atlantic Ridge is currently spreading at a rate of 2.5 cm per year (1 in per year). The mid-ocean ridges today are60,000 km (about 40,000 mi) long, forming the largest continuous mountain chain on earth. Earthquakes, faults, underwater volcanic eruptions, and vents, oropenings, along...
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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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Pollution.
One of the greatest challenges caused by air pollution is global warming, an increase in Earth’s temperature due to the buildup of certain atmospheric gases such ascarbon dioxide. With the heavy use of fossil fuels in the 20th century, atmospheric concentrations of carbon dioxide have risen dramatically. Carbon dioxide and othergases, known as greenhouse gases, reduce the escape of heat from the planet without blocking radiation coming from the Sun. Because of this greenhouse effect,average glob...
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Montana - geography.
(191 sq mi), is Montana’s largest lake, and the largest natural freshwater lake in the contiguous states west of the Mississippi River. C Climate Climatic regions in Montana coincide roughly with the two major physiographic regions. In western Montana, as compared with the eastern plains area, winters tend tobe milder while summers are cooler. Precipitation is more evenly distributed throughout the year in the west, and it is cloudier and somewhat more humid in all seasons.In addition, the grow...
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Montana - USA History.
(191 sq mi), is Montana’s largest lake, and the largest natural freshwater lake in the contiguous states west of the Mississippi River. C Climate Climatic regions in Montana coincide roughly with the two major physiographic regions. In western Montana, as compared with the eastern plains area, winters tend tobe milder while summers are cooler. Precipitation is more evenly distributed throughout the year in the west, and it is cloudier and somewhat more humid in all seasons.In addition, the grow...
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Afghanistan Facts and Figures.
Shia Muslim 15 percent Other 1 percent HEALTH AND EDUCATIONLife expectancy Total 44.2 years (2008 estimate) Female 44.4 years (2008 estimate) Male 44 years (2008 estimate) Infant mortality rate 155 deaths per 1,000 live births (2008 estimate) Population per physician 5,381 people (2004) Population per hospital bed 2,500 people (2001) Literacy rateTotal 36.3 percent (2000) Female 20.8 percent (2000) Male 51 percent (2000) Education expenditure as a share of gross national...
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Fish - biology.
pectoral fins provide fine movements, add forward thrust, or, together with the pelvic fins, serve as brakes. Typically, fins consist of a thin membrane stretched over afanlike series of thin rods called spines or rays. Most fish breathe underwater with the help of special respiratory organs called gills. Gills are made of a series of thin sheets or filaments through which blood circulates.As water moves into a fish’s mouth and passes over the gills, dissolved oxygen passes across the thin gill...
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Whale - biology.
III BEHAVIOR OF WHALES Studies of whales in captivity have taught scientists much about the complex social behavior of whales. Since the late 1980s, advances in the use of satellite trackingsystems have also broadened opportunities for scientists to observe how whales behave in the wild. A Swimming and Diving Whales swim by making powerful up-and-down movements of the tail flukes, which provide thrust. The power comes from body muscles that flex the lower spine upand down in a wavelike motion...
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Iran - country.
Zagros mountains. In the more arid central part of the country, wild pistachio and other drought-resistant trees grow in areas that have not been disturbed by humanactivity. Tamarisk and other salt-tolerant bushes grow along the margins of the Dasht-e Kavir. A wide variety of native mammals, reptiles, birds, and insects inhabit Iran. Many species of mammals—including wolves, foxes, bears, mountain goats, red mountainsheep, rabbits, and gerbils—continue to thrive. Others—including Caspian tigers,...
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Civil Rights Movement in the United States - U.
The Great Depression of the 1930s increased black protests against discrimination, especially in Northern cities. Blacks protested the refusal of white-owned businessesin all-black neighborhoods to hire black salespersons. Using the slogan “Don't Buy Where You Can't Work,” these campaigns persuaded blacks to boycott thosebusinesses and revealed a new militancy. During the same years, blacks organized school boycotts in Northern cities to protest discriminatory treatment of blackchildren. The bla...
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Moon - astronomy.
B Volcanic Features Maria, domes, rilles, and a few craters display indisputable characteristics of volcanic origin. Maria are plains of dark-colored rock that cover approximately 40 percent ofthe Moon's visible hemisphere. The maria formed when molten rock erupted onto the surface and solidified between 3.16 billion and 3.96 billion years ago. This rockresembles terrestrial basalt, a volcanic rock type widely distributed on Earth, but the rock that formed the maria has a higher iron content an...
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El Salvador - country.
III PEOPLE The Spanish subjugated the native population of El Salvador in the 16th century. Few Spanish women came to the country, however, so many Spanish men took NativeAmerican women as their mates. Today nearly 90 percent of the population is mestizo , of mixed European and Native American descent. People of purely Native American descent represent about 5 to 10 percent of the population, while people of European descent represent only about 1 percent. El Salvador’s population, 5.2 millio...
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Environment.
escape into space of the infrared energy radiated back out by Earth. This process is referred to as the greenhouse effect. These gases, primarily carbon dioxide,methane, nitrous oxide, and water vapor, insulate Earth’s surface, helping to maintain warm temperatures. Without these gases, Earth would be a frozen planet with anaverage temperature of about -18°C (about 0°F) instead of a comfortable 15°C (59°F). If the concentration of these gases rises, they trap more heat within theatmosphere, caus...
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Conservation.
cancers, Hodgkin’s disease and leukemia. Unfortunately, human activities have greatly reduced biodiversity around the world. The 20th century encompasses one of the greatest waves of extinction, orelimination of species, to occur on the planet. The greatest threat to biodiversity is loss of habitat as humans develop land for agriculture, grazing livestock, industry,and habitation. The most drastic damage has occurred in the tropical rain forests, which cover less than seven percent of the Earth’...
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Bahrain Facts and Figures.
HEALTH AND EDUCATIONLife expectancy Total 74.9 years (2008 estimate) Female 77.5 years (2008 estimate) Male 72.4 years (2008 estimate) Infant mortality rate 16 deaths per 1,000 live births (2008 estimate) Population per physician 920 people (2004) Population per hospital bed 357 people (2003) Literacy rateTotal 90 percent (2005 estimate) Female 86.4 percent (2005 estimate) Male 92.6 percent (2005 estimate) Education expenditure as a share of gross national product (GNP) 3.1 pe...
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Kuwait Facts and Figures.
Other 2 percent HEALTH AND EDUCATIONLife expectancy Total 77.5 years (2008 estimate) Female 78.7 years (2008 estimate) Male 76.4 years (2008 estimate) Infant mortality rate 9 deaths per 1,000 live births (2008 estimate) Population per physician 656 people (2004) Population per hospital bed 455 people (2002) Literacy rateTotal 84.4 percent (2005 estimate) Female 82.9 percent (2005 estimate) Male 85.8 percent (2005 estimate) Education expenditure as a share of gross national...
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Air Pollution.
Several pollutants attack the ozone layer. Chief among them is the class of chemicals known as chlorofluorocarbons (CFCs), formerly used as refrigerants (notably in airconditioners), as agents in several manufacturing processes, and as propellants in spray cans. CFC molecules are virtually indestructible until they reach thestratosphere. Here, intense ultraviolet radiation breaks the CFC molecules apart, releasing the chlorine atoms they contain. These chlorine atoms begin reacting withozone, br...
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Camel - biology.
of water in the stomach or hump as was once commonly believed. Unlike other mammals, however, the camel can survive as long as three weeks without drinking,depending on the water content of its food. It can survive a water loss of about 40 percent of its normal body weight. In comparison, a loss of 15 percent is usually fatalfor humans. Camels can go without water due to several unique adaptations to their environment. The camel conserves more water in its body than any other mammal. It excretes...
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Pakistan Facts and Figures.
HEALTH AND EDUCATIONLife expectancy Total 64.1 years (2008 estimate) Female 65.2 years (2008 estimate) Male 63.1 years (2008 estimate) Infant mortality rate 67 deaths per 1,000 live births (2008 estimate) Population per physician 1,353 people (2004) Population per hospital bed 1,429 people (2003) Literacy rateTotal 47.4 percent (2005 estimate) Female 32.4 percent (2005 estimate) Male 61.4 percent (2005 estimate) Education expenditure as a share of gross national product (GNP)...
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Hurricane.
V HOW HURRICANES ARE DETECTED AND MONITORED Since 1943 U.S. military and civilian aircraft have been flying into hurricanes to measure wind velocities and directions, the location and size of the eye, air pressures,and temperatures in different parts of the storm. A coordinated system of tracking hurricanes was developed in the mid-1950s, and steady improvements have beenmade over the years. In addition to reports from aircraft, geosynchronous weather satellites (since 1966) and ocean buoys tha...
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Biodiversity.
a common molecule, ribonucleic acid (RNA), and most also have deoxyribonucleic acid (DNA). These molecules direct the production of proteins—molecules responsiblefor the structure and function of virtually all living cells. This is the evolutionary chain of life. All species are descended from a single common ancestor. From that ancient single-celled microbe, all inherited RNA. As time goesby, species diverge and develop their own peculiar attributes, thus making their own contribution to biodiv...
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Biodiversity - biology.
a common molecule, ribonucleic acid (RNA), and most also have deoxyribonucleic acid (DNA). These molecules direct the production of proteins—molecules responsiblefor the structure and function of virtually all living cells. This is the evolutionary chain of life. All species are descended from a single common ancestor. From that ancient single-celled microbe, all inherited RNA. As time goesby, species diverge and develop their own peculiar attributes, thus making their own contribution to biodiv...
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Salt Lake City - geography.
adding a runway to the city’s airport. V GOVERNMENT Salt Lake City is governed by a mayor and a seven-member council, which is presided over by a chair. Voters elect each of these officials to four-year terms. Salt LakeCounty is governed by a county mayor elected to a four-year term and a nine-member county council. Council members—six elected from districts and three elected at-large—serve terms ranging from two to six years. The Utah Transit Authority, located in Salt Lake City, oversees publ...
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San Jose (California) - geography.
The San Jose metropolitan area is an economic powerhouse. It is the single most important high-technology center in the United States, specializing in aerospace andcomputer technology. Assisting in the area’s steady innovation is its many venture capital firms, which loan money to entrepreneurs starting new companies. It isestimated that the region contains one-half of the leading venture capital firms in the world. Among the nation’s largest companies in the San Jose metropolitan regionare Inte...
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Benjamin Harrison (1833-1901).
homesteaders against pressure from the powerful railroads. He fought vigorously for Civil War veterans, supported high taxes on imports (called tariffs), payments todisabled and opposed the Chinese Exclusion Act, which stopped Chinese immigration to the U.S. for 10 years ( see Immigration: From 1840 to 1900 ). He also introduced 101 special pension and relief bills in six years. Harrison's name was well known by the Republican National Convention in 1884. In spite of this, Congressman and forme...
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Benjamin Harrison (1833-1901) - Histoire
homesteaders against pressure from the powerful railroads. He fought vigorously for Civil War veterans, supported high taxes on imports (called tariffs), payments todisabled and opposed the Chinese Exclusion Act, which stopped Chinese immigration to the U.S. for 10 years ( see Immigration: From 1840 to 1900 ). He also introduced 101 special pension and relief bills in six years. Harrison's name was well known by the Republican National Convention in 1884. In spite of this, Congressman and forme...
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Sexually Transmitted Infections.
D Genital Herpes Genital herpes is caused by infection with the herpes simplex virus (HSV). Most cases of genital herpes are due to HSV type 2. Some cases, however, result from genitalinfections with HSV type 1, a common cause of cold sores. Genital herpes causes recurrent outbreaks of painful sores on the genitals, although the disease oftenremains dormant with no symptoms for long periods. In the United States, one in five individuals over the age of 12 is infected with HSV type 2, and the va...
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Bill Clinton.
When Arkansas governor David Pryor ran for the U.S. Senate in 1978, Clinton ran for governor. He promised to improve the state’s schools and highways and toimprove economic conditions so that more jobs would be created. At that time, the average income of people in Arkansas ranked 49th among the 50 states. Clinton woneasily, receiving 60 percent of the vote against four opponents in the Democratic primary election and 63 percent against the Republican candidate, Lynn Lowe, in thegeneral election...
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Bill Clinton - USA History.
When Arkansas governor David Pryor ran for the U.S. Senate in 1978, Clinton ran for governor. He promised to improve the state’s schools and highways and toimprove economic conditions so that more jobs would be created. At that time, the average income of people in Arkansas ranked 49th among the 50 states. Clinton woneasily, receiving 60 percent of the vote against four opponents in the Democratic primary election and 63 percent against the Republican candidate, Lynn Lowe, in thegeneral election...
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Giraffe - biology.
One of the most striking elements of giraffe behavior is the duel between males fighting for mating privileges. Giraffe duels are among the most extraordinary in theanimal kingdom. They start when two males approach each other and begin to rub and intertwine their necks. This behavior—known as necking—allows the opponentsto assess each other’s size and strength. Often, necking alone is enough to establish seniority. If not, the rivals begin to exchange blows with their heads. Each giraffebraces...
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Finland - country.
Productive forestland is the most valuable natural resource of Finland. Spruce, pine, and silver birch are the principal trees used to manufacture wood and pulp andpaper products. Finland lacks coal and petroleum resources and is a net importer of energy resources. However, Finland does have significant deposits of peat, which is cut from thenumerous peat bogs that cover much of the north. Peat is an important heat source for homes, and it provides about 7 percent of Finland’s electricity needs....
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Sierra Leone (country) - country.
commodities such as palm oil, palm kernels, coffee, cacao, ginger, kola nuts, and piassava (palm fibers) are grown for export. Cattle, goats, and sheep are raised, andthe fishing industry is of increasing importance. B Mining Gem and industrial diamonds are the leading mineral products of Sierra Leone. In 2004, 309,390 carats of gem-quality diamonds were produced. Rutile, a titanium oreof which Sierra Leone has one of the world’s largest deposits, and bauxite are also mined in large quantities....
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William Henry Harrison.
in September 1813, Harrison recaptured the city of Detroit, which the British had taken in 1812. The following month he overtook the British and Tecumseh's forces onthe Thames River in Canada. He captured the entire British force. Tecumseh was killed, and his forces were routed. Harrison's triumph on the Thames, although won over inferior forces badly placed, was vitally important because the victory secured the Northwest from the threat of aBritish invasion from Canada. It also added considerab...
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William Henry Harrison
in September 1813, Harrison recaptured the city of Detroit, which the British had taken in 1812. The following month he overtook the British and Tecumseh's forces onthe Thames River in Canada. He captured the entire British force. Tecumseh was killed, and his forces were routed. Harrison's triumph on the Thames, although won over inferior forces badly placed, was vitally important because the victory secured the Northwest from the threat of aBritish invasion from Canada. It also added considerab...
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William McKinley.
gold standard. McKinley voted for it in exchange for support for his tariff bill. His vote angered Eastern bankers and industrialists but helped lessen Western oppositionto his stand on the tariff. D Governor of Ohio Because he was a champion of protective tariffs, as well as an extremely popular politician, McKinley attracted the attention of a Cleveland industrialist, Marcus AlonzoHanna. Hanna was eager to be the maker of a president and to be the man who exercised power behind the scenes. In...
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William McKinley
gold standard. McKinley voted for it in exchange for support for his tariff bill. His vote angered Eastern bankers and industrialists but helped lessen Western oppositionto his stand on the tariff. D Governor of Ohio Because he was a champion of protective tariffs, as well as an extremely popular politician, McKinley attracted the attention of a Cleveland industrialist, Marcus AlonzoHanna. Hanna was eager to be the maker of a president and to be the man who exercised power behind the scenes. In...
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South Dakota - geography.
C1 Temperatures Average January temperatures are everywhere less than -4° C (24° F) and decrease to less than -12° C (10° F) in some northern sections. The January temperaturesin Sioux Falls range from -16° to -4° C (3° to 24° F). Nightime lows of -29° C (-20° F) occur during most winters. July averages are in the low and middle 20°s C (lowand middle 70°s F) throughout most of the state, and are somewhat lower in the Black Hills. The average temperature range in Sioux Falls in July is 17° to 30...
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South Dakota - USA History.
C1 Temperatures Average January temperatures are everywhere less than -4° C (24° F) and decrease to less than -12° C (10° F) in some northern sections. The January temperaturesin Sioux Falls range from -16° to -4° C (3° to 24° F). Nightime lows of -29° C (-20° F) occur during most winters. July averages are in the low and middle 20°s C (lowand middle 70°s F) throughout most of the state, and are somewhat lower in the Black Hills. The average temperature range in Sioux Falls in July is 17° to 30...
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United States House of Representatives.
Because of the high cost of elections and the short two-year term of office, members of the House campaign almost constantly. They spend much of their time raisingcampaign funds, and they frequently return to their districts to keep in touch with voters. Because the elections are so frequent, House members tend to pay closeattention to how their votes in Congress will be seen in the short term. House members tend to come from wealthier family backgrounds than average Americans. Few working class...
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Winston Churchill
I
INTRODUCTION
Winston Churchill (1874-1965), British politician and prime minister of the United Kingdom (1940-1945, 1951-1955), widely regarded as the greatest British leader of
the 20th century.
sufficient tools to break the stalemate on the western front and he worked on developing armored fighting vehicles (tanks) to break the deadlock and end theslaughter. As the lines hardened on the western front, Churchill focused on a campaign to force open the Dardanelles Strait, controlled by the Ottoman Empire, to give the Allies adirect route to Russia through the Black Sea. Such a move would bring much-needed supplies to the Russian armies and eliminate the Ottomans from the war. Whenthe nav...
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Winston Churchill.
sufficient tools to break the stalemate on the western front and he worked on developing armored fighting vehicles (tanks) to break the deadlock and end theslaughter. As the lines hardened on the western front, Churchill focused on a campaign to force open the Dardanelles Strait, controlled by the Ottoman Empire, to give the Allies adirect route to Russia through the Black Sea. Such a move would bring much-needed supplies to the Russian armies and eliminate the Ottomans from the war. Whenthe nav...
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Winston Churchill .
sufficient tools to break the stalemate on the western front and he worked on developing armored fighting vehicles (tanks) to break the deadlock and end theslaughter. As the lines hardened on the western front, Churchill focused on a campaign to force open the Dardanelles Strait, controlled by the Ottoman Empire, to give the Allies adirect route to Russia through the Black Sea. Such a move would bring much-needed supplies to the Russian armies and eliminate the Ottomans from the war. Whenthe nav...
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Vice President of the United States.
naval operations. Located in northwest Washington at Massachusetts Avenue and 34th Street, the three-story Queen Anne-style house is within easy driving distance ofCapitol Hill and the White House. The vice president receives an annual salary of $189,300. The vice president has a staff and offices in the Everett M. Dirksen Senate Office Building, near the Capitol, toassist with legislative matters, as well as a personal office near the Senate lobby. The vice president also has staff and offices...