Referat Earth

Mai jos puteti citi fragmente din Referat Earth si de asemenea puteti face Download Referat Earth

Citeste fragmente din Referat Earth

Earth one of the planets in the solar system, the third in distance from the sun and the fifth largest of the planets in diameter. The mean distance of the earth from the sun is 149,503,000 km (92,897,000 mi). It is the only planet known to support life, although some of the other planets have atmospheres and contain water. The earth is not a perfect sphere but is slightly oblate, or flattened at the poles. The diameter of the earth measured around the North Pole and the South Pole is about 42 km (26 mi) less than the diameter of the earth measured at the equator. COMPOSITION   The earth consists of five parts: the first, the atmosphere, is gaseous; the second, the hydrosphere, is liquid; the third, fourth, and fifth, the lithosphere, mantle, and core, are largely solid. The atmosphere is the gaseous envelope that surrounds the solid body of the planet. Although it has a thickness of more than 1100 km (more than 700 mi), about half its mass is concentrated in the lower 5.6 km (3.5 mi). The lithosphere, consisting mainly of the cold, rigid, rocky crust of the earth, extends to depths of 100 km (60 mi). The hydrosphere is the layer of water that, in the form of the oceans, covers approximately 70.8 percent of the surface of the earth. The mantle and core are the heavy interior of the earth, making up most of the earth’s mass. The hydrosphere consists chiefly of the oceans, but technically includes all water surfaces in the world, including inland seas, lakes, rivers, and underground waters. The average depth of the oceans is 3794 m (12,447 ft), more than five times the average height of the continents. The mass of the oceans is approximately 1.35 quintillion (1.35 × 1018) metric tons, or about 1/4400 of the total mass of the earth. The rocks of the lithosphere have an average density of 2.7 and are almost entirely made up of 11 elements, which together account for about 99.5 percent of its mass. The most abundant is oxygen (about 46.60 percent of the total), followed by silicon (about 27.72 percent), aluminum (8.13 percent), iron (5.0 percent), calcium (3.63 percent), sodium (2.83 percent), potassium (2.59 percent), magnesium (2.09 percent) and titanium, hydrogen, and phosphorus (totaling less than 1 percent). In addition, 11 other elements are present in trace amounts of 0.1 to 0.02 percent. These elements, in order of abundance, are carbon, manganese, sulfur, barium, chlorine, chromium, fluorine, zirconium, nickel, strontium, and vanadium. The elements are present in the lithosphere almost entirely in the form of compounds rather than in their free state. These compounds exist almost entirely in the crystalline state, so they are, by definition, minerals. The lithosphere comprises two shells—the crust and upper mantle—that are divided into a dozen or so rigid tectonic plates (see Plate Tectonics). The crust itself is divided in two. The sialic or upper crust, of which the continents consist, is made up of igneous and sedimentary rocks whose average chemical composition is similar to that of granite and whose density is about 2.7. The simatic or lower crust, which forms the floors of the ocean basins, is made of darker, heavier igneous rocks such as gabbro and basalt, with an average density of about 3. The lithosphere also includes the upper mantle. Rocks at these depths have a density of about 3.3. The upper mantle is separated from the crust above by a seismic discontinuity, called the Moho, and from the lower mantle below by a zone of weakness known as the asthenosphere. Shearing of the plastic, partially molten rocks of the asthenosphere, 100 km (60 mi) thick, enables the continents to drift across the earth’s surface and oceans to open and close. The dense, heavy interior of the earth is divided into a thick shell, the mantle, surrounding an innermost sphere, the core. The mantle extends from the base of the crust to a depth of about 2900 km (1800 mi). Except for the zone known as the asthenosphere, it is solid, and its density, increasing with depth, ranges from 3.3 to 6. The upper mantle is composed of iron and magnesium silicates, as typified by the mineral olivine. The lower part may consist of a mixture of oxides of magnesium, silicon, and iron. Seismological research has shown that the core has an outer shell about 2225 km (1380 mi) thick with an average density of 10. This shell is probably rigid, and studies show that its outer surface has depressions and peaks, the latter forming where warm material rises. In contrast, the inner core, which has a radius of about 1275 km (795 mi), is solid. Both core layers are thought to consist largely of iron, with a small percentage of nickel and other elements. Temperatures in the inner core may be as high as 6650°C (12,000°F), and the average density is estimated to be 13. Forest Conservation  Forests provide many social, economic, and environmental benefits. In addition to timber and paper products, forests provide wildlife habitat and recreational opportunities, prevent soil erosion and flooding, help provide clean air and water, and contain tremendous biodiversity. Forests are also an important defense against global climate change. Through the process of photosynthesis, forests produce life-giving oxygen and consume huge amounts of carbon dioxide, the atmospheric chemical most responsible for global warming. By decreasing the amount of carbon dioxide in the atmosphere, forests may reduce the effects of global warming. However, huge areas of the richest forests in the world have been cleared for wood fuel, timber products, agriculture, and livestock. These forests are rapidly disappearing. The tropical rainforests of the Brazilian Amazon River basin were cut down at an estimated rate of 50,000 sq km (20,000 sq mi) per year in the late 1980s. The countries with the most tropical forests tend to be developing and overpopulated nations in the southern hemisphere. Due to poor economies, people resort to clearing the forest and planting crops in order to survive. While there have been effective efforts to stop deforestation directly through boycotts of multinational corporations responsible for exploitative logging, the most effective conservation policies in these countries have been efforts to relieve poverty and expand access to education and health care. In the United States and Canada, forests are threatened by extensive logging, called clear-cutting, which destroys plant and animal habitat and leaves the landscape bare and unproductive if not properly reforested. Small pockets of ancient forests from 200 to 1200 years old still exist but are threatened by logging interests. Until the 1990s, the U.S. Forest Service was directed by Congress to maximize the harvest of timber in order to provide jobs. In the late 1980s and early 1990s, however, environmentalists sued the government for violating the National Environmental Policy Act (NEPA), and heavy logging was deemed nonsustainable. As a result, the timber harvest was reduced and foresters were directed to follow a more sustainable policy called ecosystem management. This policy required foresters to focus on conserving natural habitats rather than maximizing tree harvest. Despite this change, many ancient forests remain unprotected. Water Conservation  Clean freshwater resources are essential for drinking, bathing, cooking, irrigation, industry, and for plant and animal survival. Unfortunately, the global supply of freshwater is distributed unevenly. Chronic water shortages exist in most of Africa and drought is common over much of the globe. The sources of most freshwater supplies, groundwater (water located below the soil surface) reservoirs and rivers, are under severe and increasing environmental stress because of overuse, water pollution, and ecosystem degradation. Over 95 percent of urban sewage in developing countries is discharged untreated into surface waters such as rivers and harbors. About 65 percent of the global freshwater supply is used in agriculture and 25 percent is used in industry. Freshwater conservation therefore requires a reduction in wasteful practices like inefficient irrigation, reforms in agriculture and industry, and strict pollution controls worldwide. In addition, water supplies can be increased through effective management of watersheds (areas that drain into one shared waterway). By restoring natural vegetation to forests or fields, communities can increase the storage and filtering capacity of these watersheds and minimize wasteful flooding and erosion. Restoration and protection of wetlands is crucial to water conservation. Like giant sponges, wetlands stabilize groundwater supplies by holding rainfall and discharging the water slowly, acting as natural flood-control reservoirs. Environmental Impact Statement (EIS), formal process used to predict how a development project or proposed legislation will affect such natural resources as water, air, land, and wildlife. The environmental impact statement was first introduced in 1969 in the United States as a requirement of the National Environmental Policy Act. Since then, an increasing number of countries have adopted the process, introducing legislation and establishing agencies with responsibility for its implementation. Environmental impact statements have mostly been applied to individual projects and have led to various offshoot techniques, such as health impact assessments, social impact assessments, cumulative effects assessments, and strategic environmental assessments (environmental assessments of proposed policies, programs, and plans). In some cases, social and economic impacts are assessed as part of the environmental impact statements. In other cases, they are considered separately. An EIS usually involves a sequence of steps: (1) screening to decide if a project requires assessment and to what level of detail; (2) preliminary assessment to identify key impacts, their magnitude, significance, and importance; (3) scoping to ensure the EIS focuses on key issues and to determine where more detailed information is needed; (4) implementing the main EIS study, which involves detailed investigations to predict impacts, assess their consequences, or both. After a project is completed a post audit is sometimes done to determine how close the EIS s predictions were to the actual impacts. A growing number of businesses commission independent audits that help set environmental performance targets, particularly regarding waste disposal and energy use. The term environmental audit is applied to the voluntary regulation of an organization s practices in relation to its environmental impact. Greenpeace, international environmental organization dedicated to preserving the earth s natural resources and its diverse plant and animal life. The organization campaigns against nuclear weapons testing, environmental pollution, and destructive practices in fishing, logging, and other industries. Greenpeace was founded in Vancouver, British Columbia, Canada, in 1971 by members of the Don t Make a Wave Committee, a small group opposed to nuclear weapons testing by the United States military in Alaska. The group renamed itself Greenpeace to reflect the broader goal of creating a green and peaceful world. Greenpeace won fame for its daring exploits calculated to attract media attention to environmental issues. Greenpeace members in rubber rafts have disrupted whaling expeditions by positioning themselves between the whales and hunters harpoons. They used similar tactics in Newfoundland to protest the clubbing of baby harp seals, whose soft white fur is highly valued by clothing manufacturers. The organization is well known for scaling corporate skyscrapers and factory smokestacks to hang protest banners. Greenpeace s aggressive style has often led to conflicts with corporations, local authorities, and even national governments. In 1985 the Greenpeace ship Rainbow Warrior, on a voyage to protest French nuclear weapons testing in the Pacific, sank in a New Zealand port, and the crew photographer, Fernando Pereira, drowned. Investigations revealed that the ship had been deliberately sabotaged with explosives planted by undercover agents of the French military. The resulting scandal rocked the highest levels of the French government, leading to the resignation of Defense Minister Charles Hernu and the dismissal of Admiral Pierre Lacoste, director of the French Secret Service. During the 1990s Greenpeace has been troubled by internal disagreements over political strategy. Some members want to persist with a militant approach, emphasizing civil disobedience and physical confrontation. Other members, including the organization s leaders, are convinced that Greenpeace must work cooperatively with the companies and industries that have been its targets in the past. Greenpeace has about 3 million dues-paying members and more than 40 offices in 30 countries. Its international headquarters are in Amsterdam, Netherlands. Arctic Ocean, body of water variously identified as the smallest of four world oceans or as a virtually landlocked arm of the Atlantic Ocean. The Arctic Ocean extends south from the North Pole to the shores of Europe, Asia, and North America. I BOUNDARIES AND SIZE The surface waters of the Arctic Ocean mingle with those of the Pacific Ocean through the Bering Strait, by way of a narrow and shallow channel, which has a depth of about 55 m (about 180 ft). More importantly, the Arctic waters mix with those of the Atlantic Ocean across a system of submarine sills (shallow ridges) that span the great distances from Scotland to Greenland and from Greenland to Baffin Island at depths of about 500 to 700 m (about 1640 to 2300 ft). Emptying into the Arctic Ocean are the Ob’, Yenisey, and Lena rivers in Asia and the Mackenzie River in North America. The total surface area of the Arctic Ocean, including its major subdivisions—the North Polar Sea (the main portion), the Norwegian Sea, the North Sea, and the Barents Sea—is about 14 million sq km (about 5.4 million sq mi). II RESOURCES  Fish, in commercially exploitable quantities, are found only in the warmer marginal seas of the Arctic Ocean, notably in the North Sea (herring, cod, and flounder) and the Barents Sea (primarily cod). Sea mammals, including various species of seal and whale, were hunted to near extinction before being protected by quotas set during the 1900s. Tin is actively mined off the coast of eastern Siberia, and petroleum and natural gas are extracted north of Alaska and Canada and in the North Sea.   Atlantic Ocean, the second largest of the earth s four oceans and the most heavily traveled. Only the Pacific Ocean is larger. It covers about twice the area of the Atlantic Ocean. The Atlantic is divided into two nominal sections: The part north of the equator is called the North Atlantic; the part south of the equator, the South Atlantic. The ocean s name is derived from Atlas, one of the Titans of Greek mythology. I BOUNDARIES AND SIZE The Atlantic Ocean is essentially an S-shaped north-south channel, extending from the Arctic Ocean in the north to the Antarctic continent in the south and situated between the eastern coast of the American continents and the western coasts of Europe and Africa. The Atlantic Ocean proper has a surface area of about 82 million sq km (about 31,660,000 sq mi). Including its marginal seas—the Gulf of Mexico-Caribbean Sea, the Arctic Ocean, and the North, Baltic, Mediterranean, and Black seas—the total area is about 106,190,000 sq km (about 41 million sq mi). The boundary between the North Atlantic and the Arctic Ocean is arbitrarily designated as lying along a system of submarine ridges that extend between the land masses of Baffin Island, Greenland, and Scotland. More clearly defined is the boundary with the Mediterranean Sea at the Strait of Gibraltar and with the Caribbean Sea along the arc of the Antilles. The South Atlantic is arbitrarily separated from the Indian Ocean on the east by the 20° east meridian and from the Pacific on the west along the line of shallowest depth between Cape Horn and the Antarctic Peninsula. II MARINE RESOURCES  The Atlantic Ocean contains some of the world s most productive fisheries, located on the continental shelves and marine ridges off the British Isles, Iceland, Canada (especially the Grand Banks off Newfoundland), and the northeastern United States. Upwelling areas, in which the nutrient-rich waters of the ocean depths flow up to the surface, as in the vicinity of Walvis Bay off southwestern Africa, also have abundant sea life. Herring, anchovy, sardine, cod, flounder, and perch are the most important commercial species. Tuna is taken off northwestern Africa and northeastern South America in increasing numbers. The catch per unit area is much higher in the Atlantic than in the other oceans. A remarkable example of plant life is found in the Sargasso Sea, the oval section of the North Atlantic lying between the West Indies and the Azores and bounded on the west and north by the Gulf Stream. Here extensive patches of brown gulfweed (Sargassum) are found on the relatively still surface waters. Actively mined mineral resources in the Atlantic include titanium, zircon, and monazite (phosphates of the cerium metals), off the eastern coast of Florida, and tin and iron ore, off the equatorial coast of Africa. The continental shelves and slopes of the Atlantic are potentially very rich in fossil fuels. Large amounts of petroleum are already being extracted in the North Sea and in the Caribbean Sea-Gulf of Mexico region; lesser amounts are extracted off the coast of Africa in the Gulf of Guinea. Pacific Ocean, largest and deepest of the world s four oceans, covering more than a third of the earth s surface and containing more than half of its free water. It is sometimes divided into two nominal sections: the part north of the equator is called the North Pacific; the part south of the equator, the South Pacific. The name Pacific, which means peaceful, was given to it by the Portuguese navigator Ferdinand Magellan in 1520. I BOUNDARIES AND SIZE The Pacific Ocean is bounded on the east by the North and South American continents; on the north by the Bering Strait; on the west by Asia, the Malay Archipelago, and Australia; and on the south by Antarctica. In the southeast it is arbitrarily divided from the Atlantic Ocean by the Drake Passage along 68° west longitude; in the southwest, its separation from the Indian Ocean is not officially designated. Apart from the marginal seas along its irregular western rim, it has an area of about 165 million sq km (about 64 million sq mi), substantially larger than the entire land surface of the globe. Its maximum length is about 15,500 km (about 9600 mi) from the Bering Strait to Antarctica, and its greatest width is about 17,700 km (about 11,000 mi) from Panama to the Malay Peninsula. Its average depth is 4282 m (14,049 ft). The greatest known depth in any of the world s oceans is 11,033 m (36,198 ft) in the Mariana Trench off Guam. II RESOURCES  Much of the plant and animal life of the Pacific Ocean is concentrated along its margins. Nutrient-rich waters from the deep Antarctic Circumpolar Current upwell to the surface in the Peru Current along the coast of Chile and Peru, and the area sustains a large population of anchovetas that is of great importance as a world food resource. A large guano industry has been established from droppings of the seabirds that feed upon the anchovetas. The northwestern Pacific, including the Sea of Japan (East Sea) and the Sea of Okhotsk, is another major world fishery. Coral reefs rich with sea life reach their peak in the Great Barrier Reef, which extends for about 2010 km (about 1250 mi) along the northeastern coast of Australia. Tuna is another important Pacific resource, bringing fleets of many nations in search of the schools that migrate over much of the ocean. The Pacific has also begun to be exploited for its vast mineral resources. The continental shelves off the coasts of California, Alaska, China, and the Indonesian area are known to contain large reserves of petroleum. Patches of the ocean floor are covered with "manganese nodules," potato-sized concretions of iron and manganese oxides that sometimes also contain copper, cobalt, and nickel. Programs are under way to examine the feasibility of mining these deposits. Africa, the second largest of the earth’s seven continents, covering about 30,330,000 sq km (about 11,699,000 sq mi), including its adjacent islands. It comprises about 22 percent of the world’s total land area. In 1990 about 12 percent of the world’s population, an estimated 642 million people, lived in Africa, making it the world’s second-most populous continent after Asia. Vegetation  African vegetation can be classified according to rainfall and climate zones. The tropical rain forest zone, where the average annual rain is more than 1270 mm (more than 50 in), has a dense surface covering of shrubs, ferns, and mosses, above which tower evergreens, oil palms, and numerous species of tropical hardwood trees. A mountain forest zone, with average annual rainfall only slightly less than in the tropical rain forests, is found in the high mountains of Cameroon, Angola, eastern Africa, and parts of Ethiopia. Here a ground covering of shrubs gives way to oil palms, hardwood trees, and primitive conifers. A savanna woodland zone, with annual rainfall of 890 to 1400 mm (35 to 55 in), covers vast areas with a layer of grass and fire-resistant shrubs, above which are found deciduous and leguminous fire-resistant trees. A savanna grassland zone, with annual rainfall of about 500 to 890 mm (about 20 to 35 in), is covered by low grasses and shrubs and scattered, small deciduous trees. The thornbush zone, a steppe vegetation, with an annual rainfall of about 300 to 510 mm (about 12 to 20 in), has a thinner grass covering and a scattering of succulent or semisucculent trees. The subdesert scrub zone, with an annual rainfall of 130 to 300 mm (5 to 12 in), has a covering of grasses and scattered low shrubs. The zone of desert vegetation, found in areas with an annual rainfall of less than 130 mm (less than 5 in), has sparse vegetation or none at all. Animal Life  Africa has two distinct zones of animal life: the North and Northwestern zone, including the Sahara; and the Ethiopian zone, including all of sub-Saharan Africa. The North and Northwestern zone is characterized by animals similar to those of Eurasia. Sheep, goats, horses, and camels are common. Barbary sheep, African red deer, and two types of ibex are native to the northern African coast. Desert foxes are found in the Sahara along with hares, gazelles, and the jerboa, a small leaping rodent. The Ethiopian zone is famous for its great variety of distinctive animals and birds. Woodland and grassland areas are inhabited by numerous species of antelope and deer, zebra, giraffe, buffalo, the African elephant, rhinoceros, and the baboon and various monkeys. Carnivores, or meat-eating animals, include the lion, leopard, cheetah, hyena, jackal, and mongoose. The gorilla, the largest ape in the world, inhabits the rain forests of equatorial Africa, as do monkeys, flying squirrels, bats and lemurs. Most bird life belongs to Eurasian groups. The guinea fowl is a leading game bird. Water birds, notably pelicans, goliath herons, flamingos, storks, and egrets, congregate in great numbers. The ibis is common in the Nile region, and the ostrich is found in eastern and southern Africa. Reptiles are mainly of Eurasian origin and include lizards, crocodiles, and tortoises. A variety of venomous snakes, including the mamba, are encountered throughout the Ethiopian zone. Among the constricting snakes, pythons are found mainly in western Africa; boa constrictors are indigenous only to Madagascar. Freshwater fish abound, with more than 2000 species known. The continent has a variety of destructive insects, notably mosquitoes, driver ants, termites, locusts, and tsetse flies. The last named transmit sleeping sickness to humans and animals (in animals, the disease is called nagana). Mineral Resources  Africa is very rich in mineral resources, possessing most of the known mineral types of the world, many of which are found in significant quantities, although the geographic distribution is uneven. Fossil fuels are abundant, including major deposits of coal, petroleum, and natural gas. Africa has some of the world’s largest reserves of gold, diamonds, copper, bauxite, manganese, nickel, platinum, cobalt, radium, germanium, lithium, titanium, and phosphates. Other important mineral resources include iron ore, chromium, tin, zinc, lead, thorium, zirconium, vanadium, antimony, and beryllium. Also found in exploitable quantities are clays, mica, sulfur, salt, natron, graphite, limestone, and gypsum. Agriculture  Despite the expansion of commerce and industry and the importance of these activities to the economy, most Africans remain farmers and herders. In northern and northwestern Africa, wheat, oats, corn, and barley are the important grain crops. Dates, olives, and citrus fruit are the main tree crops; a variety of vegetables are grown. Goats and sheep are the most significant livestock raised. In the Sahara region, nomadic herders raise camels, and a few farmers situated in oases grow dates and grains. South of the Sahara, shifting agriculture—a method in which small areas were burned, cleared, and planted and then allowed to revert to bush—has given way in most areas to settled farming. Grain is the main crop outside the rain forests; rice, yams, cassava, okra, plantains, and bananas are raised for food. Cattle cannot be raised in tsetse fly-infested areas, which cover more than one-third of the continent. Outside tsetse fly areas and dense forests, cattle are raised in large numbers, primarily for beef. Dairy farming is limited, located mainly around urban centers in eastern and southern Africa. Although some 60 percent of all cultivated land is in subsistence agriculture, commercial or cash-crop farming is common in all parts of the continent. Foodstuffs are grown for local urban markets, but coffee, cotton, cacao (cocoa beans), peanuts, palm oil, and tobacco are grown by Africans for export. For certain agricultural exports, such as cacao (cocoa beans), peanuts, cloves, and sisal, Africa produces more than one-half of the world supply. European-owned plantations and farms, found mainly in eastern and southern Africa, concentrate on citrus, tobacco, and other export foodstuffs. Forestry and Fishing  Although about one-quarter of Africa is covered by forest, much of the timber has little value except as local fuel. Gabon is a major producer of okoume, a wood used in making plywood; Côte d’Ivoire, Liberia, Ghana, and Nigeria are major exporters of hardwoods. Inland fishing is concentrated in the Great Rift Valley lakes and in the increasing numbers of fish farms. Ocean fishing is widespread for local consumption; it is commercially important off Morocco, Namibia, and South Africa. Mining  Mineral extraction provides the bulk of African export earnings, and extractive industries are the most developed sectors in most African economies. Approximately one-half of Africa’s mineral income comes from South Africa; much of this is derived from gold and diamond mining. The other leading mineral-producing countries are Libya (petroleum), Nigeria (petroleum, natural gas, coal, tin), Algeria (petroleum, natural gas, iron ore), and Zambia (copper, cobalt, coal, lead, zinc). Petroleum is also found along the western African coast, in the Gabon Basin, the Republic of the Congo, the DRC, and Angola. Large quantities of uranium are also mined, chiefly in South Africa, Niger, the DRC, the Central African Republic, and Gabon. The largest radium supply in the world is located in the DRC. Some 20 percent of the world copper reserve is concentrated in Zambia, the DRC, South Africa, and Zimbabwe. The DRC also possesses about 90 percent of the world’s known cobalt, and Sierra Leone has the largest known titanium reserves. Africa produces some three-quarters of the world’s gold; South Africa, followed by Zimbabwe, the DRC, and Ghana, are the major producers. The mines of South Africa and the DRC produce virtually the entire world supply of gem and industrial diamonds. Iron ore is found in all parts of the continent. Most of Africa’s mineral wealth has been and is being developed by large, multinational concerns. Increasingly, in recent years, African governments have become substantial shareholders in the operations within their own countries. Manufacturing  Stemming from mineral and petroleum extraction are processing industries, such as refining and smelting, which are located in most mineral-rich countries with adequate energy. The bulk of Africa’s manufacturing takes place in South Africa. Heavy industry, such as metal producing, machine making, and transportation manufacturing, is concentrated in South Africa. Significant industrial centers have also developed in Zimbabwe, Egypt, and Algeria. Mineral-related industries are well developed in the DRC and Zambia; Kenya, Nigeria, and Côte d’Ivoire have developed primarily in textiles, light industry, and building materials. Throughout much of the rest of Africa, manufacturing is limited to making or assembling consumer goods, such as shoes, bicycles, textiles, food, and beverages. Such industries are often confined by the relatively small size of the consumer market. Energy  Nigeria, Libya, Algeria, and Angola are major world producers of petroleum. Africa’s natural-gas exports are centered in Algeria. Coal is concentrated in Zimbabwe and South Africa; the bulk of their production is used internally. The rest of Africa must import fuels. Although Africa has some 40 percent of the world’s hydropower potential, only a relatively small portion has been developed due to high construction costs, inaccessibility of sites, and their distance from markets. Since 1960, however, a number of major hydroelectric installations have been constructed; these include the Aswân High Dam on the Nile River, the Akosombo Dam on the Volta River, and the Kariba Dam and Cabora Bassa Dam on the Zambezi River. Algeria officially Democratic and Popular Republic of Algeria, republic of western North Africa; bounded on the north by the Mediterranean Sea; on the east by Tunisia and Libya; on the south by Niger, Mali, and Mauritania; and on the west by Morocco. Its total area is 2,381,741 sq km (919,595 sq mi). Natural Resources  Most of the natural wealth of Algeria lies in its sizable mineral deposits, notably crude petroleum, natural gas, phosphates, and iron ore. Other minerals include coal, lead, and zinc. The arable land comprises only about 3 percent of the total area and is located mainly in the valleys and plains of the coastal region. Plants and Animals  The northern sections of Algeria have suffered from centuries of deforestation and overgrazing. Remnants of forests exist in a few areas of the higher Tell and Saharan Atlas. Trees include pines, Atlas cedar, and various oaks, including cork oak. Lower slopes are bare or covered with a scrub vegetation of juniper and other shrubs. Much of the High Plateau is barren, but tracts of steppe vegetation containing esparto grass and brushwood are present. Plant life in the Sahara is widely scattered and consists of drought-resistant grasses, acacia, and jujube trees. The relatively sparse vegetation of the country can support only a limited wildlife population. Scavengers, such as jackals, hyenas, and vultures, are found in most regions. Fewer antelope, hares, gazelles, and reptiles are also present. Soils  Rich soils are rare in Algeria. The most fertile lands, located in the Tell region, nearest the coast, are relatively poor in humus and have suffered from overcultivation. The plains have considerable alluvial deposits, but the uplands have poorer soils and can support only grasses suitable for grazing. Angola, formerly Portuguese West Africa, officially Republic of Angola, independent state in southwestern Africa. Angola is bounded on the north and east by the Democratic Republic of the Congo (DRC, formerly Zaire), on the east by Zambia, on the south by Namibia, and on the west by the Atlantic Ocean. A small exclave, Cabinda, is located some 30 km (about 20 mi) to the north and is bounded on the north by the Republic of the Congo, on the east and south by the DRC, and on the west by the Atlantic Ocean. Angola has a coastline of about 1600 km (about 1000 mi) and a total area of 1,246,700 sq km (481,350 sq mi). The capital and largest city is Luanda. LAND AND RESOURCES  Angola is the seventh largest country in Africa, covering an area greater than France and Spain combined. Mineral Resources  Angola is rich in mineral resources, and further geological exploration is likely to add to the list of known mineral reserves. Among the most notable resources are petroleum, diamonds, iron ore, manganese, copper, uranium, phosphates, and salt. Vegetation and Animal Life  Vegetation varies with the climate. Thick tropical rain forests are found in the north and in the Cabinda exclave. To the south the rain forests give way to savanna, lands of mixed trees and grasses, which in turn grade into grasslands on the south and east. Palm trees are found on much of the coast, and sparse desert vegetation grows south of Namibe. Wildlife is as diverse as the vegetation and includes many of the larger African mammals, such as elephants, rhinoceroses, giraffes, hippopotamuses, zebras, antelope, lions, and gorillas. Also found are crocodiles and various birds and insects. Forestry and Fishing The rich rain forests of Cabinda and the northwest furnished 7 million cu m (247 million cu ft) of roundwood for fuel and industrial purposes in 1995. Because of the cool Benguela Current, the waters off the coast of Angola are particularly rich in marine life. Fishing has thus been a traditionally important activity; in 1995 the total catch was 80,723 metric tons, primarily mackerel and sardines. Namibe and Lobito are the principal fishing ports. Mining  Petroleum accounts for 90 percent of national exports by value. Most production is from the offshore fields of Cabinda, which were first exploited in the 1960s. The total output of crude petroleum in 1996 was 259 million barrels. Diamonds remain the second most important mineral. Output in 1996 was 4.0 million carats; nearly all were of gem quality. Iron ore, formerly the third most important mineral, has not been produced commercially since 1975 because the mines were partially destroyed during the civil war. Production of salt and natural gas has continued, despite the disruption of the war. Manufacturing  The development of the industrial sector has been limited. The principal manufactured products are beverages and processed foods, such as refined sugar, fish meal, flour, and beer. Other products include textiles, cement, glass, and chemicals. Petroleum refineries are located in Cabinda and at Luanda. Energy  Angola has great hydroelectric potential in the numerous streams that descend from the central plateau. Hydroelectric plants have been constructed on the Cuanza, Cunene, Dande, and Catumbela rivers. The total production of electric energy in 1996 was 1.9 billion kilowatt-hours, 75 percent of which was generated from hydroelectric plants. At present Angola’s power production potential exceeds its needs. Benin, republic in western Africa, on the Gulf of Guinea. Known in full as the Republic of Benin, it extends inland about 670 km (about 415 mi) from its 121-km (75-mi) long gulf coast. Benin is bordered on the north by Burkina Faso and Niger, on the east by Nigeria, and on the west by Togo. Formerly part of French West Africa, it gained independence in 1960 as Dahomey; it was named Benin in 1975. It has an area of 112,622 sq km (43,484 sq mi). Porto-Novo is the capital and Cotonou is the largest city. LAND AND RESOURCES  The coast of Benin is a sandy barrier beach with no natural harbors. Immediately north of the beach is a network of shallow lagoons, and farther north is a fertile lowland called the barre country, most of which is intensively cultivated. In northern Benin the land rises to include the edge of a nearly 500-m (1600-ft) high plateau of ancient rocks and mostly infertile soils and, in the northwest, the rugged Atakora Mountains. Rivers and Lakes  The Ouémé and Kouffo rivers drain most of southern Benin, and the Mono River, which forms part of the border with Togo, drains the southwest. The main rivers of northern Benin are the Niger, which forms part of the boundary with the republic of Niger, and its tributaries, the Sota, Mékrou, and Alibori rivers. Plants and Animals  A dense tropical rain forest once covered much of the land close behind Benin s coastal strip. The rain forest has largely been cleared, except near rivers, and palms now are the main trees of the region. Woodlands form a large part of central Benin, and grasslands predominate in the drier north. Among the various animals found in Benin are elephants, buffalo, antelope, panthers, monkeys, crocodiles, and wild ducks. Natural Resources  An offshore petroleum field is located near Cotonou. Other mineral resources of Benin include iron ore, phosphates, chromium, rutile, clay, marble, and limestone. Forestry and Fishing  Commercial forestry and fishing are largely undeveloped in Benin. Almost all of the estimated 5.9 million cu m (208 million cu ft) of wood cut in 1995 was used for fuel. Similarly, most of the 39,000 metric tons of fish produced annually are caught in inland rivers and in lagoons for subsistence use. Relatively small amounts of shrimp are landed on a commercial basis. Mining and Manufacturing  Benin s chief mineral product is petroleum, although reserves are believed to be nearing exhaustion. Some limestone is also produced for use in cement manufacturing, and gold is exploited and used by artisans. Most other mineral resources are undeveloped. The chief manufacturing activity is the processing of primary products. Industry includes palm oil processing operations, textile mills, a cement plant, and a sugar-refining complex. A wire and steel manufacturing plant recently opened. Cameroon, republic in western Africa, bounded on the north by Lake Chad; on the east by Chad and the Central African Republic; on the south by the Republic of the Congo, Gabon, and Equatorial Guinea; and on the west by the Bight of Biafra (an arm of the Atlantic Ocean) and Nigeria. The country is shaped like an elongated triangle, and forms a bridge between western Africa and central Africa. The country has a total area of 475,442 sq km (183,569 sq mi). Yaoundé is the capital, and Douala is the largest city. LAND AND RESOURCES  Cameroon has four distinct topographical regions. In the south is a coastal plain, a region of dense equatorial rain forests. In the center is the Adamawa Plateau, a region with elevations reaching about 1370 m (about 4500 ft) above sea level. This is a transitional area where forest gives way in the north to savanna country. In the far north the savanna gradually slopes into the marshland surrounding Lake Chad. In the west is an area of high, forested mountains of volcanic origin. Located here is Cameroon Mountain (4095 m/13,435 ft), the highest peak in western Africa and an active volcano. The country’s most fertile soils are found in this region. Among the principal streams, the Sanaga and Nyong rivers flow generally west to the Atlantic Ocean, and the Mbéré and Logone rivers flow north from the central plateau into Lake Chad. A network of rivers in the Chad Basin, including the Benue River, links the country with the vast Niger River system to the east and north. Plants and Animals  Cameroon’s valuable rain forests contain a number of species of trees, including oil palms, bamboo palms, mahogany, teak, ebony, and rubber. Wildlife is diverse and abundant and includes monkeys, chimpanzees, gorillas, antelope, lions, and elephants, as well as numerous species of birds and snakes. Natural Resources  The economy of Cameroon is dependent primarily on its agricultural and timber resources, although receipts from petroleum reserves constitute a primary source of government revenue. High-yield deposits of bauxite exist in northern Cameroon. A significant reserve of natural gas is found near Douala, but it remains unexploited. A small amount of gold is mined. Hydroelectric potential is significant; the largest power station is at Edéa, on the Sanaga River. Agriculture  The principal commercial crops in Cameroon are cacao, coffee, tobacco, cotton, and bananas. In 1997 production of cacao and coffee, the leading agricultural export commodities, was 120,000 metric tons for the former and 60,000 metric tons for the latter. Other commercial products include rubber, palm products, and sugarcane. Subsistence crops include plantains, sweet potatoes, cassava, corn, and millet. Livestock raising is important in the Adamawa Plateau region. In 1997 the livestock population included 4.9 million head of cattle, 3.8 million goats, 3.8 million million sheep, and 1.4 million pigs. Forestry and Fishing  Timber is traditionally one of Cameroon’s most valuable exports, consisting mainly of mahogany, ebony, and teak. The timber cut in 1995 amounted to 15.7 million cu m (555 million cu ft). Fishing is dominated by freshwater subsistence activity. However, deep-sea fishing activity is increasing, especially from the port of Douala. Some 80,000 metric tons of fish are caught annually. Mining and Manufacturing  One of the largest single industrial enterprises in Cameroon is the aluminum smelting plant at Edéa, which produces 92,000 metric tons annually from imported bauxite. The processing of agricultural products, however, dominates industrial activity; other manufactures include textiles, fertilizers, and cement. Offshore petroleum exploitation began in the late 1970s, and an oil refinery has been built on the coast at Limboh Point. Cameroon’s output of crude petroleum, mostly for export, was 34 million barrels in 1996. Small amounts of gold and tin concentrates are also produced. Central African Republic, republic in central Africa, bordered on the north by Chad, on the east by Sudan, on the south by the Democratic Republic of the Congo (DRC, formerly Zaire) and the Republic of the Congo, and on the west by Cameroon. The landlocked nation has an area of 622,436 sq km (240,324 sq mi). Bangui is the capital and largest city. LAND AND RESOURCES  The Central African Republic is situated on the northern edge of the Congo River Basin. Most of the land is a plateau that ranges in elevation from about 610 to 790 m (about 2000 to 2600 ft). Two ranges of hills in the north and northeast rise to maximum heights of about 1400 m (about 4600 ft). Most of the country has a savanna vegetation—a grassland interspersed with trees. Open grassland is found in the extreme north, and a dense rain forest covers the major part of the southwestern area. The country is drained by several major rivers, the Bamingui and Ouham rivers in the north, and the Ubangi, a tributary of the Congo, in the south. Natural Resources  The mineral resources of this primarily agricultural country are relatively undeveloped. Diamonds are the dominant exploited mineral. Deposits of uranium exist, as well as iron ore, gold, lime, zinc, copper, and tin. Commercially valuable trees include the sapele mahogany and the obeche. Almost every animal of the African Tropics is found in the country. Agriculture and Forestry  Only 3 percent of the total land area is used for growing crops. Basic food crops include cassava, plantains, corn, peanuts, sweet potatoes, and millet. In order to increase the wage-earning power of the peasant farmer, the government has organized agricultural cooperatives, placing primary emphasis on introducing new crops that are expected to produce a higher income. The cultivation of tobacco, sesame, and rice is encouraged by the government. The most important cash crop is coffee, once grown mostly on European-owned plantations, but now produced largely on smaller African-owned farms. In 1997 coffee production was 18,000 metric tons. Cotton, which is widely cultivated, is also a leading cash crop and represents a significant portion of export earnings. Exploitation of forest reserves was slow to develop but has increased in importance. In 1995 some 3.9 million cu m (136 million cu ft) of roundwood were produced. Timber accounted for 8 percent of export revenues in the early 1990s. Manufacturing and Mining  Manufacturing activity in the Central African Republic is very limited. Products include cottonseed, peanut, and sesame oils; textiles; leather goods; tobacco products; soap; flour; bricks; and paint. The output of electricity in 1996 was 100 million kilowatt-hours, 80 percent of which was generated in hydroelectric installations. Gem diamonds account for nearly all the country s mineral output and two-thirds of its export revenue. Production was 350,000 carats in 1996. Uranium was discovered in the eastern part of the country in 1966, but production is awaiting improvement in international prices. A small amount of gold is mined, mostly by individual prospectors. Republic of the Congo, republic in west central Africa, bounded on the north by Cameroon and the Central African Republic, on the east and south by the Democratic Republic of the Congo (DRC, formerly Zaire), on the southwest by Angola (Cabinda enclave) and the Atlantic Ocean, and on the west by Gabon. Formerly called People’s Republic of the Congo, the republic has an area of 342,000 sq km (132,000 sq mi). Brazzaville is the capital and largest city. LAND AND RESOURCES  Along the Atlantic coast is a low, treeless plain, which rises inland to the Mayumbe Mountains, an almost completely forested region with an average elevation of about 550 m (about 1800 ft). In the south central region is the fertile valley of the Niari River. To the north lies the central highlands region, the Plateau Batéké. The plateau is cut by numerous tributaries of the Congo and Ubangi rivers. The Congo Basin occupies the northeastern part of the country. Dense tropical rain forests cover more than half of the country and constitute a major natural resource. The principal commercial species are okoumé (a mahogany) and limba (a hardwood). Savanna vegetation is found in the northeast and the higher plateau areas. Wildlife is diverse and abundant, including antelope, giraffes, cheetahs, crocodiles, and numerous birds and snakes. The climate is tropical, with mostly high heat and humidity. While the Mayumbe Mountains experience a long dry season, parts of the Congo Basin receive more than 2500 mm (more than 100 in) of rainfall annually. Average temperatures in Brazzaville are 26° C (78° F) in January and 23° C (73° F) in July, with an annual rainfall of about 1500 mm (about 60 in). Temperatures along the coast are slightly cooler. Petroleum, found offshore, is the Congo’s principal mineral resource. Other resources include potash, gold, iron ore, lead, and copper. Agriculture  Cassava, pineapples, plantains, bananas, peanuts, maize, and avocados are the principal subsistence crops raised in the Congo. The main cash crops are sugarcane, palm kernels, cacao, and coffee. The most successful commercial agricultural operations are in the fertile Niari Valley. Forestry and Mining  Forest products account for a substantial share of the Congo’s exports. Petroleum is produced from offshore oil fields, and crude oil typically accounts for about three-quarters of the country’s yearly exports. The output of crude petroleum in 1995 was 64 million barrels and is expected to increase as a new offshore field is developed. In addition, natural gas, lead, copper, and gold are mined. Manufacturing  Industry is oriented mainly toward producing consumer goods. The largest industries process agricultural products (including tobacco) and forest products. Other manufactures include textiles, cement, footwear, and soap. A petroleum refinery began operation at Pointe-Noire in 1976. Egypt, officially Arab Republic of Egypt, country in northeastern Africa and southwestern Asia. It is bounded on the north by the Mediterranean Sea, on the east by Israel and the Red Sea, on the south by Sudan, and on the west by Libya. The country has a maximum length from north to south of about 1085 km (about 675 mi) and a maximum width, near the southern border, of about 1255 km (about 780 mi). It has a total area of 997,739 sq km (385,229 sq mi). Cairo is the capital and largest city. The land of the Nile River, Egypt is the cradle of one of the world’s greatest ancient civilizations and has a recorded history that dates from about 3200 BC. The descriptive material that follows is pertinent to modern Egypt. The History section covers Egypt from ancient times, including the Dynastic Period (3200 BC-343 BC), the Hellenistic Period (332 BC-30 BC), Roman and Byzantine Rule (30 BC-AD 638), the Caliphate and the Mamelukes (642-1517), Ottoman Domination (1517-1882), and British colonialism (1882-1952) as well as modern, independent Egypt (1952- ). LAND AND RESOURCES  Less than one-tenth of the land area of Egypt is settled or under cultivation. This territory consists of the valley and delta of the Nile, a number of desert oases, and land along the Suez Canal. More than 90 percent of the country consists of desert areas, including the Libyan Desert in the west, a part of the Sahara, and the Arabian Desert (also called the Eastern Desert), which borders the Red Sea and the Gulf of Suez, in the east. The Libyan Desert (also known as the Western Desert) includes a vast sandy expanse called the Great Sand Sea. Located here are several depressions with elevations below sea level, including the Qattara Depression, which has an area of about 18,000 sq km (about 7000 sq mi) and reaches a depth of 133 m (436 ft) below sea level; also found here are the oases of Siwa, Khârijah, Baḩrîyah, Farafra, and Dakhla. Much of the Arabian Desert occupies a plateau that rises gradually east from the Nile Valley to elevations of about 600 m (about 2000 ft) in the east and is broken along the Red Sea coast by jagged peaks as high as about 2100 m (about 7000 ft) above sea level. In the extreme south, along the border with Sudan, is the Nubian Desert, an extensive region of dunes and sandy plains. The Sinai Peninsula consists of sandy desert in the north and rugged mountains in the south, with summits looming more than about 2100 m (about 7000 ft) above the Red Sea. Mount Catherine (Jabal Katrînah) (2637 m/8652 ft), the highest elevation in Egypt, is in the Sinai Peninsula, as is Mount Sinai (Jabal Mosá), where, according to the Old Testament, Moses received the Ten Commandments. The Nile enters Egypt from Sudan and flows north for about 1545 km (about 960 mi) to the Mediterranean Sea. For its entire length from the southern border to Cairo, the Nile flows through a narrow valley lined by cliffs. Lake Nasser, a huge reservoir formed by the Aswân High Dam, extends south across the Sudan border. The lake is about 480 km (about 300 mi) long and is 16 km (10 mi) across at its widest point. About two-thirds of the lake lies in Egypt. South of a point near the town of Idfû, the Nile Valley is rarely more than 3 km (2 mi) wide. From Idfû to Cairo, the valley averages 23 km (14 mi) in width, with most of the arable portion on the western side. In the vicinity of Cairo the valley merges with the delta, a fan-shaped plain, the perimeter of which occupies about 250 km (about 155 mi) of the Mediterranean coastline. Silt deposited by the Rosetta (Arabic Rashid), Damietta (Arabic Dumyat), and other distributaries has made the delta the most fertile region in the country. However, the Aswân High Dam has reduced the flow of the Nile, causing the salty waters of the Mediterranean to erode land along the coast near the Nile. A series of four shallow, brackish lakes extends along the seaward extremity of the delta. Another larger lake, Birkat Qârûn, is situated inland in the desert north of the town of Al Fayyûm. Geographically and traditionally, the Nile Valley is divided into two regions, Lower Egypt and Upper Egypt, the former consisting of the delta area and the latter comprising the valley south of Cairo. Although Egypt has about 2450 km (1520 mi) of coastline, two-thirds of which are on the Red Sea, indentations suitable as harbors are confined to the delta. The Isthmus of Suez, which connects the Sinai Peninsula with the African mainland, is traversed from the Mediterranean to the Gulf of Suez by the Suez Canal. Natural Resources  Egypt has a wide variety of mineral deposits, some of which, such as gold and red granite, have been exploited since ancient times. The chief mineral resource of contemporary value is petroleum, found mainly in the Red Sea coastal region, at Al ‘Alamayn (El ‘Alamein) on the Mediterranean, and in the Sinai Peninsula. Other minerals include phosphates, manganese, iron ore, and uranium. Natural gas is also extracted. Plants and Animals  The vegetation of Egypt is confined largely to the Nile delta, the Nile Valley, and the oases. The most widespread of the few indigenous trees is the date palm. Others include the sycamore, tamarisk, acacia, and carob. Trees that have been introduced from other lands include the cypress, elm, eucalyptus, mimosa, and myrtle, and various types of fruit trees. The alluvial soils of Egypt, especially in the delta, sustain a broad variety of plant life, including grapes, many kinds of vegetables, and such flowers as the lotus, jasmine, and rose. In the arid regions alfa grass and several species of thorn are common. Papyrus, once prevalent along the banks of the Nile, is now limited to the extreme south of the country. Because of its arid climate Egypt has few indigenous wild animals. Gazelles are found in the deserts, and the desert fox, hyena, jackal, wild ass, boar, jerboa, and ichneumon inhabit various areas, mainly the delta and the mountains along the Red Sea. Among the reptiles of Egypt are lizards and several kinds of poisonous snakes, including the asp and the horned viper. The crocodile and hippopotamus, common in the lower Nile and Nile delta in antiquity, are now restricted to the upper Nile. Birdlife is abundant, especially in the Nile delta and Nile Valley. The country has approximately 300 species of birds, including the sunbird, golden oriole, egret, hoopoe, plover, pelican, flamingo, heron, stork, quail, and snipe. Birds of prey found in Egypt include eagles, falcons, vultures, owls, kites, and hawks. Many species of insects are found in Egypt—beetles, mosquitoes, flies, and fleas being especially numerous; scorpions are found in desert areas. About 100 species of fish can be found in the Nile and in the deltaic lakes. Agriculture  Egypt is predominantly an agricultural country, with about 40 percent of the labor force engaged in crop farming, herding, or fishing. The pattern of land ownership was greatly altered by the Agricultural Reform Decree of 1952, which limited individual holdings to about 80 hectares (about 200 acres), a figure revised in 1961 to about 40 hectares (about 100 acres), and revised again to about 20 hectares (about 50 acres) in 1969. Lands requisitioned by the government were distributed to the fellahin (peasants), but an economic gap still remains between the middle-class farmers and the fellahin. Government programs have expanded arable areas through reclamation, irrigation (notably since the completion of the Aswân High Dam in 1970), and the use of advanced technology (fertilizers, mechanized equipment). The yields of Egyptian farmlands are now among the highest in the world. Egypt is one of the world’s leading producers of long-staple (long-fibered) cotton. Annual cotton lint production in 1997 was about 890,000 metric tons. Warm weather and plentiful water permit as many as three crops a year, giving Egypt abundant agricultural yields. In the early 1990s principal crops, ranked by estimated value and annual production in metric tons, included rice (3.9 million), tomatoes (4.7 million), wheat (4.6 million), maize (5.2 million), sugarcane (11.6 million), potatoes (1.8 million), and oranges (1.7 million). A wide variety of other vegetables and fruits are also grown. The principal pastoral industry of Egypt is the breeding of beasts of burden. The livestock population in 1997 included 2.7 million cattle, 2.8 million buffalo, 3.5 million sheep, 3.2 million goats, 1.7 million asses, and 52 million poultry. Fishing  Egypt has a significant fishing industry. In 1995 the annual catch was 302,800 metric tons. Among the most productive areas are the shallow deltaic lakes, Birkat Qârûn, and the Red Sea. The formerly productive sardine fisheries along the Mediterranean coast have been greatly depleted since the construction of the Aswân High Dam. A fishing industry is being developed in Lake Nasser. Mining  Crude petroleum, which accounts for 37 percent of export earnings, is the most important mineral product of Egypt. Production was about 26.4 million barrels annually in the early 1960s. As a result of the discovery in the 1950s and 1960s of large new fields in the Al ‘Alamayn and Gulf of Suez areas, and a major exploration effort in the 1970s, annual production of crude petroleum increased to 337 million barrels in 1996. Proven reserves stood at 6.2 billion barrels in 1992 as Egypt renewed exploration, signing 12 agreements with foreign companies to drill new wells. The country is encouraging natural gas production to supply domestic energy needs, with annual extraction in 1996 of 17.9 billion cu m (631 billion cu ft). Other important products of the mining industry in the early 1990s included phosphate rock (1.5 million metric tons), iron ore (1.2 million tons metal content), and salt (1.1 million tons). Uranium ore began to be mined near Aswân in 1991. Republic of South Africa southernmost country in Africa, bordered on the north by Namibia, Botswana, Zimbabwe, Mozambique, and Swaziland; on the east and south by the Indian Ocean; and on the west by the Atlantic Ocean. Lesotho forms an enclave in the northeastern part of the country. South Africa has a diverse and dramatic landscape. Most of the interior is covered by high plateaus, which are separated from the country’s long coastline by chains of tall mountains. South Africa is rich in minerals such as gold and diamonds, and its industrial base grew up around the mining industry. Black Africans comprise three quarters of South Africa’s population, and whites, Coloureds (people of mixed race), and Asians (mainly Indians) make up the remainder. Among the black population there are numerous ethnic groups and 11 official languages. Until recently, whites dominated the nonwhite majority population under the political system of racial segregation known as apartheid. Apartheid ended in the early 1990s, but South Africa is still recovering from the racial inequalities in political power, opportunity, and lifestyle. The end of apartheid led to the lifting of trade sanctions against South Africa imposed by the international community. It also led to a total reorganization of the government, which since 1994 has been a nonracial democracy based on majority rule. South Africa is divided into nine provinces. These provinces are Gauteng, Northern Province, Mpumalanga, North-West Province, Free State, Eastern Cape, Northern Cape, Western Cape, and KwaZulu-Natal. The country has three capitals: Cape Town is the legislative capital; Pretoria, the executive capital; and Bloemfontein, the judicial capital. LAND AND RESOURCES  South Africa stretches for some 1500 km (950 mi) from east to west and 1000 km (640 mi) from north to south. It has an area of 1,219,090 sq km (470,693 sq mi). A ridge called the Great Escarpment forms a boundary between the interior plateaus and the coastal regions. Natural Regions  The interior plateaus occupy about two-thirds of South Africa, reaching their greatest height in the southeastern Drakensberg Mountains, part of the Great Escarpment. Champagne Castle, a peak of the Drakensberg, is the highest point in the country at 3375 m (11,072 ft). The plateau region consists of three main areas: the High Veld, the Middle Veld, and the Bush Veld. The High Veld, the largest of the three areas, is the southern continuation of the great African plateau that stretches north to the Sahara Desert. In South Africa it ranges in elevation from about 1200 to 1800 m (about 4000 to 6000 ft) and is characterized by level or gently sloping terrain. Land use varies from cattle grazing in the west to mixed farming (both crops and livestock) in the center to growing grain, especially maize (corn), in the east. The northern boundary of the High Veld is marked by the gold-bearing reef of the Witwatersrand, which became the industrial heartland of South Africa in the 20th century. West of the High Veld is the Middle Veld, which lies mainly at an elevation of 600 to 1200 m (2000 to 4000 ft). The Middle Veld is part of the larger Kalahari Basin that extends north to Botswana and Namibia and contains the southernmost portion of the Kalahari Desert. Surface water is rare in the Middle Veld because the soils, which consist largely of unconsolidated sand, quickly absorb rainfall. Plant life in this arid place is limited to drought-resistant grasses, bushes, and shrubs. Much of the area is used for sheep grazing. North of the High Veld is the Bush Veld (also called the Transvaal Basin). This region averages less than 1200 m (4000 ft) in elevation. It is broken into basins by rock ridges, and slopes downward from the Transvaal Drakensberg in the east to the Limpopo River in the west. The Bush Veld receives more rain than the High Veld or Middle Veld and includes large areas of intensive cultivation as well as mixed-farming and cattle-grazing districts. Between the edge of the high central plateau region and the eastern and southern coastline the land descends in a series of abrupt steps. In the east an interior belt of hill country gives way to a low-lying plain known as the Eastern Low Veld. In the south two plateaus, the Great, or Central, Karoo and the Little, or Southern, Karoo, are situated above the coastal plain. The plateau of the Great Karoo is separated from the lower Little Karoo by the Swartberg mountain range. A second range, the Langeberg, separates the Little Karoo from the coastal plain. Both the plateaus and the coastal plain are areas of mixed farming. The southwestern edge of the central plateau region is marked by irregular ranges of folded mountains which descend abruptly to a narrow coastal plain, broken by the isolated peak of Table Mountain. The lower parts of this southwestern region are the centers of wine and fruit industries. Rivers and Lakes  The chief rivers are the Orange, Vaal, and Limpopo. The Orange is the longest, stretching about 2100 km (about 1300 mi). It rises in Lesotho, where it is called the Senqu, and flows northwestward to the Atlantic, forming the boundary with Namibia along the river’s westernmost section. The Vaal rises in the northeast, near Swaziland, and flows southwestward to its confluence with the Orange. The Limpopo rises further north, flowing northeastward to the Botswana border and then eastward along the Botswana and Zimbabwe borders until it enters Mozambique, where it empties into the Indian Ocean. Many shorter rivers flow south to the Indian Ocean, including the Sondags, Great Fish, and Kei