1.
Tropic of Capricorn
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The Tropic of Capricorn is the circle of latitude that contains the subsolar point on the December solstice. It is thus the southernmost latitude where the Sun can be directly overhead and its northern equivalent is the Tropic of Cancer. The Tropic of Capricorn is one of the five major circles of latitude that mark maps of the Earth. As of 3 April 2017, its latitude is 23°26′13. 4″ south of the equator, the Tropic of Capricorn is the dividing line between the Southern Temperate Zone to the south and the tropics to the north. The northern hemisphere equivalent of the Tropic of Capricorn is the Tropic of Cancer, the position of the Tropic of Capricorn is not fixed, but rather it varies in a complex manner over time, see under circles of latitude for information. In southern Africa, where rainfall is more reliable, farming is possible, vegetation here is almost non-existent, though on the eastern slopes of the Andes rainfall is adequate for rainfed agriculture. In modern times the sun appears in the constellation Sagittarius during this time, the change is due to precession of the equinoxes. The word tropic itself comes from the Greek trope, meaning turn, change in direction or circumstances, referring to the fact that the sun appears to turn back at the solstices
2.
Equator
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The Equator usually refers to an imaginary line on the Earths surface equidistant from the North Pole and South Pole, dividing the Earth into the Northern Hemisphere and Southern Hemisphere. The Equator is about 40,075 kilometres long, some 78. 7% lies across water and 21. 3% over land, other planets and astronomical bodies have equators similarly defined. Generally, an equator is the intersection of the surface of a sphere with the plane that is perpendicular to the spheres axis of rotation. The latitude of the Earths equator is by definition 0° of arc, the equator is the only line of latitude which is also a great circle — that is, one whose plane passes through the center of the globe. The plane of Earths equator when projected outwards to the celestial sphere defines the celestial equator, in the cycle of Earths seasons, the plane of the equator passes through the Sun twice per year, at the March and September equinoxes. To an observer on the Earth, the Sun appears to travel North or South over the equator at these times, light rays from the center of the Sun are perpendicular to the surface of the Earth at the point of solar noon on the Equator. Locations on the Equator experience the quickest sunrises and sunsets because the sun moves nearly perpendicular to the horizon for most of the year. The Earth bulges slightly at the Equator, the diameter of the Earth is 12,750 kilometres. Because the Earth spins to the east, spacecraft must also launch to the east to take advantage of this Earth-boost of speed, seasons result from the yearly revolution of the Earth around the Sun and the tilt of the Earths axis relative to the plane of revolution. During the year the northern and southern hemispheres are inclined toward or away from the sun according to Earths position in its orbit, the hemisphere inclined toward the sun receives more sunlight and is in summer, while the other hemisphere receives less sun and is in winter. At the equinoxes, the Earths axis is not tilted toward the sun, instead it is perpendicular to the sun meaning that the day is about 12 hours long, as is the night, across the whole of the Earth. Near the Equator there is distinction between summer, winter, autumn, or spring. The temperatures are usually high year-round—with the exception of high mountains in South America, the temperature at the Equator can plummet during rainstorms. In many tropical regions people identify two seasons, the wet season and the dry season, but many places close to the Equator are on the oceans or rainy throughout the year, the seasons can vary depending on elevation and proximity to an ocean. The Equator lies mostly on the three largest oceans, the Pacific Ocean, the Atlantic Ocean, and the Indian Ocean. The highest point on the Equator is at the elevation of 4,690 metres, at 0°0′0″N 77°59′31″W and this is slightly above the snow line, and is the only place on the Equator where snow lies on the ground. At the Equator the snow line is around 1,000 metres lower than on Mount Everest, the Equator traverses the land of 11 countries, it also passes through two island nations, though without making a landfall in either. Starting at the Prime Meridian and heading eastwards, the Equator passes through, Despite its name, however, its island of Annobón is 155 km south of the Equator, and the rest of the country lies to the north
3.
Brisbane
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Brisbane is the capital of and most populous city in the Australian state of Queensland, and the third most populous city in Australia. Brisbanes metropolitan area has a population of 2.35 million, the Brisbane central business district stands on the original European settlement and is situated inside a bend of the Brisbane River, about 15 kilometres from its mouth at Moreton Bay. The demonym of Brisbane is Brisbanite, one of the oldest cities in Australia, Brisbane was founded upon the ancient homelands of the indigenous Turrbal and Jagera peoples. A penal settlement was founded in 1824 at Redcliffe,28 kilometres north of the business district. The city was marred by the Australian frontier wars between 1843 and 1855, and development was set back by the Great Fire of Brisbane. Brisbane was chosen as the capital when Queensland was proclaimed a colony from New South Wales in 1859. During World War II, Brisbane played a role in the Allied campaign. Today, Brisbane is well known for its distinct Queenslander architecture which forms much of the built heritage. It also receives attention for its damaging flood events, most notably in 1974 and 2011. Several large cultural, international and sporting events have held at Brisbane, including the 1982 Commonwealth Games, World Expo 88, the final Goodwill Games in 2001. Prior to white settlement, the Brisbane area was inhabited by the Turrbal and they knew the area that is now the central business district as Mian-jin, meaning place shaped as a spike. The Moreton Bay area was explored by Matthew Flinders. On 17 July 1799, Flinders landed at what is now known as Woody Point, in 1823 Governor of New South Wales Sir Thomas Brisbane instructed that a new northern penal settlement be developed, and an exploration party led by John Oxley further explored Moreton Bay. Oxley discovered, named, and explored the Brisbane River as far as Goodna,20 kilometres upstream from the Brisbane central business district, Oxley recommended Red Cliff Point for the new colony, reporting that ships could land at any tide and easily get close to the shore. The party settled in Redcliffe on 13 September 1824, under the command of Lieutenant Henry Miller with 14 soldiers and 29 convicts. However, this settlement was abandoned after a year and the colony was moved to a site on the Brisbane River now known as North Quay,28 km south, chief Justice Forbes gave the new settlement the name of Edenglassie before it was named Brisbane. Non-convict European settlement of the Brisbane region commenced in 1838, German missionaries settled at Zions Hill, Nundah as early as 1837, five years before Brisbane was officially declared a free settlement. The band consisted of ministers Christopher Eipper and Carl Wilhelm Schmidt and lay missionaries Haussmann, Johann Gottried Wagner, Niquet, Hartenstein, Zillman, Franz, Rode, Doege and they were allocated 260 hectares and set about establishing the mission, which became known as the German Station
4.
Queensland
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Queensland is the second-largest and third-most-populous state in the Commonwealth of Australia. Situated in the north-east of the country, it is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west, to the east, Queensland is bordered by the Coral Sea and Pacific Ocean. Queensland has a population of 4,750,500, concentrated along the coast, the state is the worlds sixth largest sub-national entity, with an area of 1,852,642 km2. The capital and largest city in the state is Brisbane, Australias third largest city, often referred to as the Sunshine State, Queensland is home to 10 of Australias 30 largest cities and is the nations third largest economy. Tourism in the state, fuelled largely by its tropical climate, is a major industry. Queensland was first inhabited by Aboriginal Australians and Torres Strait Islanders, the first European to land in Queensland was Dutch navigator Willem Janszoon in 1606, who explored the west coast of the Cape York Peninsula near present-day Weipa. In 1770, Lieutenant James Cook claimed the east coast of Australia for the Kingdom of Great Britain. The colony of New South Wales was founded in 1788 by Governor Arthur Phillip at Sydney, New South Wales at that time included all of what is now Queensland, Queensland was explored in subsequent decades until the establishment of a penal colony at Brisbane in 1824 by John Oxley. Penal transportation ceased in 1839 and free settlement was allowed from 1842, the state was named in honour of Queen Victoria, who on 6 June 1859 signed Letters Patent separating the colony from New South Wales. The 6th of June is now celebrated statewide as Queensland Day. Queensland achieved statehood with the Federation of Australia on 1 January 1901, the history of Queensland spans thousands of years, encompassing both a lengthy indigenous presence, as well as the eventful times of post-European settlement. The north-eastern Australian region was explored by Dutch, Spanish and French navigators before being encountered by Lieutenant James Cook in 1770, the Australian Labor Party has its origin as a formal organisation in Queensland and the town of Barcaldine is the symbolic birthplace of the party. June 2009 marked the 150th anniversary of its creation as a colony from New South Wales. The Aboriginal occupation of Queensland is thought to predate 50,000 BC, likely via boat or land bridge across Torres Strait, during the last ice age Queenslands landscape became more arid and largely desolate, making food and other supplies scarce. This led to the worlds first seed-grinding technology, warming again made the land hospitable, which brought high rainfall along the eastern coast, stimulating the growth of the states tropical rainforests. In February 1606, Dutch navigator Willem Janszoon landed near the site of what is now Weipa and this was the first recorded landing of a European in Australia, and it also marked the first reported contact between European and Aboriginal Australian people. The region was explored by French and Spanish explorers prior to the arrival of Lieutenant James Cook in 1770. Cook claimed the east coast under instruction from King George III of the United Kingdom on 22 August 1770 at Possession Island, naming Eastern Australia, including Queensland, the Aboriginal population declined significantly after a smallpox epidemic during the late 18th century
5.
Naples
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Naples is the capital of the Italian region Campania and the third-largest municipality in Italy, after Rome and Milan. In 2015, around 975,260 people lived within the administrative limits. The Metropolitan City of Naples had a population of 3,115,320, Naples is the 9th-most populous urban area in the European Union with a population of between 3 million and 3.7 million. About 4.4 million people live in the Naples metropolitan area, Naples is one of the oldest continuously inhabited cities in the world. Bronze Age Greek settlements were established in the Naples area in the second millennium BC, a larger colony – initially known as Parthenope, Παρθενόπη – developed on the Island of Megaride around the ninth century BC, at the end of the Greek Dark Ages. Naples remained influential after the fall of the Western Roman Empire, thereafter, in union with Sicily, it became the capital of the Two Sicilies until the unification of Italy in 1861. Naples was the most-bombed Italian city during World War II, much of the citys 20th-century periphery was constructed under Benito Mussolinis fascist government, and during reconstruction efforts after World War II. The city has experienced significant economic growth in recent decades, and unemployment levels in the city, however, Naples still suffers from political and economic corruption, and unemployment levels remain high. Naples has the fourth-largest urban economy in Italy, after Milan, Rome and it is the worlds 103rd-richest city by purchasing power, with an estimated 2011 GDP of US$83.6 billion. The port of Naples is one of the most important in Europe, numerous major Italian companies, such as MSC Cruises Italy S. p. A, are headquartered in Naples. The city also hosts NATOs Allied Joint Force Command Naples, the SRM Institution for Economic Research, Naples is a full member of the Eurocities network of European cities. The city was selected to become the headquarters of the European institution ACP/UE and was named a City of Literature by UNESCOs Creative Cities Network, the Villa Rosebery, one of the three official residences of the President of Italy, is located in the citys Posillipo district. Naples historic city centre is the largest in Europe, covering 1,700 hectares and enclosing 27 centuries of history, Naples has long been a major cultural centre with a global sphere of influence, particularly during the Renaissance and Enlightenment eras. In the immediate vicinity of Naples are numerous culturally and historically significant sites, including the Palace of Caserta, culinarily, Naples is synonymous with pizza, which originated in the city. Neapolitan music has furthermore been highly influential, credited with the invention of the romantic guitar, according to CNN, the metro stop Toledo is the most beautiful in Europe and it won also the LEAF Award 2013 as Public building of the year. Naples is the Italian city with the highest number of accredited stars from the Michelin Guide, Naples sports scene is dominated by football and Serie A club S. S. C. Napoli, two-time Italian champions and winner of European trophies, who play at the San Paolo Stadium in the south-west of the city, the Phlegraean Fields around Naples has been inhabited since the Neolithic period. The earliest Greek settlements were established in the Naples area in the second millennium BC, sailors from the Greek island of Rhodes established a small commercial port called Parthenope on the island of Megaride in the ninth century BC
6.
Italy
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Italy, officially the Italian Republic, is a unitary parliamentary republic in Europe. Located in the heart of the Mediterranean Sea, Italy shares open land borders with France, Switzerland, Austria, Slovenia, San Marino, Italy covers an area of 301,338 km2 and has a largely temperate seasonal climate and Mediterranean climate. Due to its shape, it is referred to in Italy as lo Stivale. With 61 million inhabitants, it is the fourth most populous EU member state, the Italic tribe known as the Latins formed the Roman Kingdom, which eventually became a republic that conquered and assimilated other nearby civilisations. The legacy of the Roman Empire is widespread and can be observed in the distribution of civilian law, republican governments, Christianity. The Renaissance began in Italy and spread to the rest of Europe, bringing a renewed interest in humanism, science, exploration, Italian culture flourished at this time, producing famous scholars, artists and polymaths such as Leonardo da Vinci, Galileo, Michelangelo and Machiavelli. The weakened sovereigns soon fell victim to conquest by European powers such as France, Spain and Austria. Despite being one of the victors in World War I, Italy entered a period of economic crisis and social turmoil. The subsequent participation in World War II on the Axis side ended in defeat, economic destruction. Today, Italy has the third largest economy in the Eurozone and it has a very high level of human development and is ranked sixth in the world for life expectancy. The country plays a prominent role in regional and global economic, military, cultural and diplomatic affairs, as a reflection of its cultural wealth, Italy is home to 51 World Heritage Sites, the most in the world, and is the fifth most visited country. The assumptions on the etymology of the name Italia are very numerous, according to one of the more common explanations, the term Italia, from Latin, Italia, was borrowed through Greek from the Oscan Víteliú, meaning land of young cattle. The bull was a symbol of the southern Italic tribes and was often depicted goring the Roman wolf as a defiant symbol of free Italy during the Social War. Greek historian Dionysius of Halicarnassus states this account together with the legend that Italy was named after Italus, mentioned also by Aristotle and Thucydides. The name Italia originally applied only to a part of what is now Southern Italy – according to Antiochus of Syracuse, but by his time Oenotria and Italy had become synonymous, and the name also applied to most of Lucania as well. The Greeks gradually came to apply the name Italia to a larger region, excavations throughout Italy revealed a Neanderthal presence dating back to the Palaeolithic period, some 200,000 years ago, modern Humans arrived about 40,000 years ago. Other ancient Italian peoples of undetermined language families but of possible origins include the Rhaetian people and Cammuni. Also the Phoenicians established colonies on the coasts of Sardinia and Sicily, the Roman legacy has deeply influenced the Western civilisation, shaping most of the modern world
7.
Los Angeles
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Los Angeles, officially the City of Los Angeles and often known by its initials L. A. is the cultural, financial, and commercial center of Southern California. With a census-estimated 2015 population of 3,971,883, it is the second-most populous city in the United States, Los Angeles is also the seat of Los Angeles County, the most populated county in the United States. The citys inhabitants are referred to as Angelenos, historically home to the Chumash and Tongva, Los Angeles was claimed by Juan Rodríguez Cabrillo for Spain in 1542 along with the rest of what would become Alta California. The city was founded on September 4,1781, by Spanish governor Felipe de Neve. It became a part of Mexico in 1821 following the Mexican War of Independence, in 1848, at the end of the Mexican–American War, Los Angeles and the rest of California were purchased as part of the Treaty of Guadalupe Hidalgo, thereby becoming part of the United States. Los Angeles was incorporated as a municipality on April 4,1850, the discovery of oil in the 1890s brought rapid growth to the city. The completion of the Los Angeles Aqueduct in 1913, delivering water from Eastern California, nicknamed the City of Angels, Los Angeles is known for its Mediterranean climate, ethnic diversity, and sprawling metropolis. Los Angeles also has an economy in culture, media, fashion, science, sports, technology, education, medicine. A global city, it has been ranked 6th in the Global Cities Index, the city is home to renowned institutions covering a broad range of professional and cultural fields, and is one of the most substantial economic engines within the United States. The Los Angeles combined statistical area has a gross metropolitan product of $831 billion, making it the third-largest in the world, after the Greater Tokyo and New York metropolitan areas. The city has hosted the Summer Olympic Games in 1932 and 1984 and is bidding to host the 2024 Summer Olympics and thus become the second city after London to have hosted the Games three times. The Los Angeles area also hosted the 1994 FIFA mens World Cup final match as well as the 1999 FIFA womens World Cup final match, the mens event was watched on television by over 700 million people worldwide. The Los Angeles coastal area was first settled by the Tongva, a Gabrielino settlement in the area was called iyáangẚ, meaning poison oak place. Gaspar de Portolà and Franciscan missionary Juan Crespí, reached the present site of Los Angeles on August 2,1769, in 1771, Franciscan friar Junípero Serra directed the building of the Mission San Gabriel Arcángel, the first mission in the area. The Queen of the Angels is an honorific of the Virgin Mary, two-thirds of the settlers were mestizo or mulatto with a mixture of African, indigenous and European ancestry. The settlement remained a small town for decades, but by 1820. Today, the pueblo is commemorated in the district of Los Angeles Pueblo Plaza and Olvera Street. New Spain achieved its independence from the Spanish Empire in 1821, during Mexican rule, Governor Pío Pico made Los Angeles Alta Californias regional capital
8.
Mexican Plateau
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The Central Mexican Plateau, also known as the Mexican Altiplano, is a large arid-to-semiarid plateau that occupies much of northern and central Mexico. A low east-west mountain range in the state of Zacatecas divides the plateau into northern and southern sections and these two sections, called the Northern Plateau and Central Plateau, are now generally regarded by geographers as sections of one plateau. The Mexican Plateau is mostly covered by deserts and xeric shrublands, with forests covering the surrounding mountain ranges. The Mexican Altiplano is one of six distinct sections of the Basin and Range Province. In phytogeography, the Sonoran Desert is within the Sonoran Floristic Province of the Madrean Region in southwestern North America, various narrow, isolated ridges cross the Mesa del Norte and numerous depressions also dot the region, the largest of which is the Bolsón de Mapimí. The Río Bravo del Norte and its tributary, the Río Conchos, drain portions of the plateau. Both drain to the Gulf of Mexico, much of the northern plateau comprises internal drainage basins that do not drain to the sea. The Mesa Central or southern plateau is higher than its northern counterpart, the southern plateau contains numerous valleys originally formed by ancient lakes. It extends across the states of Aguascalientes, Jalisco, Zacatecas, Guanajuato, Querétaro, Michoacán, México, several of Mexicos most prominent cities, including Mexico City and Guadalajara, are located in the valleys of the southern plateau. Much of the plateau is drained by the Río Grande de Santiago and its tributaries, including the Río Lerma. Tributaries of the Río Pánuco drain the eastern portion of the southern plateau, the Central Mexican matorral covers much of the southern plateau, with the subtropical Bajío dry forests occupying the lower portions of the Lerma–Río Grande de Santiago basin. Higher altitudes are covered by Mixed Forests, then Temperate Coniferous Forests and this article incorporates public domain material from the Library of Congress Country Studies website http, //lcweb2. loc. gov/frd/cs/. Ricketts, Taylor H. Eric Dinerstein, David M. Olson, Colby J. Loucks, terrestrial Ecoregions of North America, a Conservation Assessment. Image Science and Analysis Laboratory, NASA-Johnson Space Center, earth from Space - Image Information
9.
Vietnam
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Vietnam, officially the Socialist Republic of Vietnam, is the easternmost country on the Indochina Peninsula in Southeast Asia. With an estimated 92.7 million inhabitants as of 2016, it is the worlds 14th-most-populous country, and its capital city has been Hanoi since the reunification of North and South Vietnam in 1976, with Ho Chi Minh City as a historical city as well. The northern part of Vietnam was part of Imperial China for over a millennium, an independent Vietnamese state was formed in 939, following a Vietnamese victory in the Battle of Bạch Đằng River. Following a Japanese occupation in the 1940s, the Vietnamese fought French rule in the First Indochina War, thereafter, Vietnam was divided politically into two rival states, North Vietnam, and South Vietnam. Conflict between the two sides intensified in what is known as the Vietnam War, the war ended with a North Vietnamese victory in 1975. Vietnam was then unified under a communist government but remained impoverished, in 1986, the government initiated a series of economic and political reforms which began Vietnams path towards integration into the world economy. By 2000, it had established relations with all nations. Since 2000, Vietnams economic growth rate has been among the highest in the world and its successful economic reforms resulted in its joining the World Trade Organization in 2007. It is also a member of the Asia-Pacific Economic Cooperation and the Organisation Internationale de la Francophonie, Vietnam remains one of the worlds four remaining one-party socialist states officially espousing communism. The name Việt Nam is a variation of Nam Việt, a name that can be traced back to the Triệu Dynasty of the 2nd century BC. The word Việt originated as a form of Bách Việt. The form Vietnam is first recorded in the 16th-century oracular poem Sấm Trạng Trình, the name has also been found on 12 steles carved in the 16th and 17th centuries, including one at Bao Lam Pagoda in Haiphong that dates to 1558. Then, as recorded, rewarded Yuenan/Vietnam as their nations name, to also show that they are below the region of Baiyue/Bach Viet. Between 1804 and 1813, the name was used officially by Emperor Gia Long and it was revived in the early 20th century by Phan Bội Châus History of the Loss of Vietnam, and later by the Vietnamese Nationalist Party. The country was usually called Annam until 1945, when both the government in Huế and the Viet Minh government in Hanoi adopted Việt Nam. Archaeological excavations have revealed the existence of humans in what is now Vietnam as early as the Paleolithic age, Homo erectus fossils dating to around 500,000 BC have been found in caves in Lạng Sơn and Nghệ An provinces in northern Vietnam. The oldest Homo sapiens fossils from mainland Southeast Asia are of Middle Pleistocene provenance, teeth attributed to Homo sapiens from the Late Pleistocene have also been found at Dong Can, and from the Early Holocene at Mai Da Dieu, Lang Gao and Lang Cuom. The Hồng Bàng dynasty of the Hùng kings is considered the first Vietnamese state, in 257 BC, the last Hùng king was defeated by Thục Phán, who consolidated the Lạc Việt and Âu Việt tribes to form the Âu Lạc, proclaiming himself An Dương Vương
10.
Taiwan
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Taiwan, officially the Republic of China, is a state in East Asia. Neighbours include China to the west, Japan to the northeast, Taiwan is the most populous state that is not a member of the United Nations, and the one with the largest economy. The island of Taiwan, also known as Formosa, was inhabited by Taiwanese aborigines before the 17th century. After a brief rule by the Kingdom of Tungning, the island was annexed by the Qing dynasty, the Qing ceded Taiwan to Japan in 1895 after the Sino-Japanese War. While Taiwan was under Japanese rule, the Republic of China was established on the mainland in 1912 after the fall of the Qing dynasty, following the Japanese surrender to the Allies in 1945, the ROC took control of Taiwan. However, the resumption of the Chinese Civil War led to the ROCs loss of the mainland to the Communists, and the flight of the ROC government to Taiwan in 1949. As a founding member of the United Nations, the ROC continued to represent China at the United Nations until 1971, in the early 1960s, Taiwan entered a period of rapid economic growth and industrialization, creating a stable industrial economy. In the 1980s and early 1990s, it changed from a one-party military dictatorship dominated by the Kuomintang to a multi-party democracy with universal suffrage, Taiwan is the 22nd-largest economy in the world, and its high-tech industry plays a key role in the global economy. It is ranked highly in terms of freedom of the press, health care, public education, economic freedom, the PRC has consistently claimed sovereignty over Taiwan and asserted the ROC is no longer in legitimate existence. Under its One-China Policy the PRC refused diplomatic relations with any country that recognizes the ROC, the PRC has threatened the use of military force in response to any formal declaration of independence by Taiwan or if PRC leaders decide that peaceful unification is no longer possible. There are various names for the island of Taiwan in use today, the former name Formosa dates from 1542, when Portuguese sailors sighted the main island of Taiwan and named it Ilha Formosa, which means beautiful island. The name Formosa eventually replaced all others in European literature and was in use in English in the early 20th century. This name was adopted into the Chinese vernacular as the name of the sandbar. The modern word Taiwan is derived from this usage, which is seen in forms in Chinese historical records. Use of the current Chinese name was formalized as early as 1684 with the establishment of Taiwan Prefecture, through its rapid development, the entire Formosan mainland eventually became known as Taiwan. The official name of the state is the Republic of China and it was a member of the United Nations representing China until 1971, when it lost its seat to the Peoples Republic of China. Over subsequent decades, the Republic of China has become known as Taiwan. In some contexts, especially ones from the ROC government
11.
Earth
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Earth, otherwise known as the World, or the Globe, is the third planet from the Sun and the only object in the Universe known to harbor life. It is the densest planet in the Solar System and the largest of the four terrestrial planets, according to radiometric dating and other sources of evidence, Earth formed about 4.54 billion years ago. Earths gravity interacts with objects in space, especially the Sun. During one orbit around the Sun, Earth rotates about its axis over 365 times, thus, Earths axis of rotation is tilted, producing seasonal variations on the planets surface. The gravitational interaction between the Earth and Moon causes ocean tides, stabilizes the Earths orientation on its axis, Earths lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. About 71% of Earths surface is covered with water, mostly by its oceans, the remaining 29% is land consisting of continents and islands that together have many lakes, rivers and other sources of water that contribute to the hydrosphere. The majority of Earths polar regions are covered in ice, including the Antarctic ice sheet, Earths interior remains active with a solid iron inner core, a liquid outer core that generates the Earths magnetic field, and a convecting mantle that drives plate tectonics. Within the first billion years of Earths history, life appeared in the oceans and began to affect the Earths atmosphere and surface, some geological evidence indicates that life may have arisen as much as 4.1 billion years ago. Since then, the combination of Earths distance from the Sun, physical properties, in the history of the Earth, biodiversity has gone through long periods of expansion, occasionally punctuated by mass extinction events. Over 99% of all species that lived on Earth are extinct. Estimates of the number of species on Earth today vary widely, over 7.4 billion humans live on Earth and depend on its biosphere and minerals for their survival. Humans have developed diverse societies and cultures, politically, the world has about 200 sovereign states, the modern English word Earth developed from a wide variety of Middle English forms, which derived from an Old English noun most often spelled eorðe. It has cognates in every Germanic language, and their proto-Germanic root has been reconstructed as *erþō, originally, earth was written in lowercase, and from early Middle English, its definite sense as the globe was expressed as the earth. By early Modern English, many nouns were capitalized, and the became the Earth. More recently, the name is simply given as Earth. House styles now vary, Oxford spelling recognizes the lowercase form as the most common, another convention capitalizes Earth when appearing as a name but writes it in lowercase when preceded by the. It almost always appears in lowercase in colloquial expressions such as what on earth are you doing, the oldest material found in the Solar System is dated to 4. 5672±0.0006 billion years ago. By 4. 54±0.04 Gya the primordial Earth had formed, the formation and evolution of Solar System bodies occurred along with the Sun
12.
Savanna
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A savanna or savannah is a mixed woodland grassland ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support a herbaceous layer consisting primarily of grasses. Savannas maintain an open canopy despite a high tree density and it is often believed that savannas feature widely spaced, scattered trees. However, in savannas, tree densities are higher and trees are more regularly spaced than in forests. Savanna covers approximately 20% of the Earths land area, the word originally entered English in 1555 as the Latin Zauana, equivalent in the orthography of the times to zavana. Peter Martyr reported it as the name for the plain around Comagre. The accounts are inexact, but this is placed in present-day Madugandí or at points on the nearby Guna Yala coast opposite Ustupo or on Point Mosquitos. These areas are now given over to modern cropland or jungle. The common usage meaning to describe vegetation now conflicts with a simplified yet widespread climatic concept meaning, the divergence has sometimes caused areas such as extensive savannas north and south of the Congo and Amazon Rivers to be excluded from mapped savanna categories. Barrens has been used almost interchangeably with savanna in different parts of North America, sometimes midwestern savanna were described as grassland with trees. Different authors have defined the limits of savanna tree coverage as 5–10%. Two factors common to all environments are rainfall variations from year to year. In the Americas, e. g. in Belize, Central America, savanna vegetation is similar from Mexico to South America, savannas are subject to regular wildfires and the ecosystem appears to be the result of human use of fire. For example, Native Americans created the Pre-Columbian savannas of North America by periodically burning where fire-resistant plants were the dominant species, pine barrens in scattered locations from New Jersey to coastal New England are remnants of these savannas. Aboriginal burning appears to have responsible for the widespread occurrence of savanna in tropical Australia and New Guinea. The maquis shrub savannas of the Mediterranean region were created and maintained by anthropogenic fire. These fires are usually confined to the layer and do little long term damage to mature trees. However, these either kill or suppress tree seedlings, thus preventing the establishment of a continuous tree canopy which would prevent further grass growth
