Past

The past is the set of all events that occurred before a given point in time. 　The past is contrasted with and defined by the present and the future. 　The concept of the past is derived from the linear fashion in which human observers experience time, and is accessed through memory and recollection. 　In addition, human beings have recorded the past since the advent of written language. 　The first known use of the word "past" was in the fourteenth century; it developed as the past participle of the middle English verb passen meaning "to pass."

Structure

A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. 　Material structures include man-made objects such as buildings and machines and natural objects such as biological organisms, minerals and chemicals. 　Abstract structures include data structures in computer science and musical form. 　Types of structure include a hierarchy (a cascade of one-to-many relationships), a network featuring many-to-many links, or a lattice featuring connections between components that are neighbors in space.

Professional

A professional is a member of a profession or any person who works in a specified professional activity. 　The term also describes the standards of education and training that prepare members of the profession with the particular knowledge and skills necessary to perform their specific role within that profession. 　In addition, most professionals are subject to strict codes of conduct, enshrining rigorous ethical and moral obligations. 　Professional standards of practice and ethics for a particular field are typically agreed upon and maintained through widely recognized professional associations, such as the IEEE. 　Some definitions of "professional" limit this term to those professions that serve some important aspect of public interest and the general good of society. 　In some cultures, the term is used as shorthand to describe a particular social stratum of well-educated workers who enjoy considerable work autonomy and who are commonly engaged in creative and intellectually challenging work.

Star

A star is an astronomical object comprising a luminous spheroid of plasma held together by its gravity. 　The nearest star to Earth is the Sun. 　Many other stars are visible to the naked eye at night, but their immense distances from Earth make them appear as fixed points of light. 　The most prominent stars have been categorised into constellations and asterisms, and many of the brightest stars have proper names. 　Astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations. 　The observable universe contains an estimated 1022 to 1024 stars. 　Only about 4,000 of these stars are visible to the naked eye, all within the Milky Way galaxy. 　A star's life begins with the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements. 　Its total mass is the main factor determining its evolution and eventual fate. 　A star shines for most of its active life due to the thermonuclear fusion of hydrogen into helium in its core. 　This process releases energy that traverses the star's interior and radiates into outer space. 　At the end of a star's lifetime, its core becomes a stellar remnant: a white dwarf, a neutron star, or—if it is sufficiently massive—a black hole. 　Stellar nucleosynthesis in stars or their remnants creates almost all naturally occurring chemical elements heavier than lithium. 　Stellar mass loss or supernova explosions return chemically enriched material to the interstellar medium. 　These elements are then recycled into new stars. 　Astronomers can determine stellar properties—including mass, age, metallicity (chemical composition), variability, distance, and motion through space—by carrying out observations of a star's apparent brightness, spectrum, and changes in its position in the sky over time. 　Stars can form orbital systems with other astronomical objects, as in the case of planetary systems and star systems with two or more stars. 　When two such stars have a relatively close orbit, their gravitational interaction can significantly impact their evolution. 　Stars can form part of a much larger gravitationally bound structure, such as a star cluster or a galaxy.

Science

Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe. 　Systematic reasoning is tens of thousands of years old. 　The earliest written records of identifiable predecessors to modern science come from Ancient Egypt and Mesopotamia from around 3000 to 1200 BCE. 　Their contributions to mathematics, astronomy, and medicine entered and shaped the Greek natural philosophy of classical antiquity, whereby formal attempts were made to provide explanations of events in the physical world based on natural causes.　: 12  After the fall of the Western Roman Empire, knowledge of Greek conceptions of the world deteriorated in Western Europe during the early centuries (400 to 1000 CE) of the Middle Ages, but was preserved in the Muslim world during the Islamic Golden Age and later by the efforts of Byzantine Greek scholars who brought Greek manuscripts from the dying Byzantine Empire to Western Europe in the Renaissance. 　The recovery and assimilation of Greek works and Islamic inquiries into Western Europe from the 10th to 13th century revived "natural philosophy", which was later transformed by the Scientific Revolution that began in the 16th century as new ideas and discoveries departed from previous Greek conceptions and traditions. 　The scientific method soon played a greater role in knowledge creation and it was not until the 19th century that many of the institutional and professional features of science began to take shape, along with the changing of "natural philosophy" to "natural science". 　Modern science is typically divided into three major branches: natural sciences (e.g., biology, chemistry, and physics), which study the physical world; the social sciences (e.g., economics, psychology, and sociology), which study individuals and societies; and the formal sciences (e.g., logic, mathematics, and theoretical computer science), which study formal systems, governed by axioms and rules. 　There is disagreement whether the formal sciences are science disciplines, because they do not rely on empirical evidence. 　Applied sciences are disciplines that use scientific knowledge for practical purposes, such as in engineering and medicine. 　New knowledge in science is advanced by research from scientists who are motivated by curiosity about the world and a desire to solve problems. 　Contemporary scientific research is highly collaborative and is usually done by teams in academic and research institutions, government agencies, and companies. 　The practical impact of their work has led to the emergence of science policies that seek to influence the scientific enterprise by prioritizing the ethical and moral development of commercial products, armaments, health care, public infrastructure, and environmental protection.

Reached

Reached is a 2012 young adult dystopian novel by Allyson Braithwaite Condie and is the final novel in the Matched Trilogy, preceded by Matched and Crossed. 　The novel was published on November 13, 2012, by Dutton Juvenile and was set to have a first printing of 500,000 copies. 　The novel is told from the viewpoints of Cassia, Ky, and Xander, a point that Condie insisted on. 　The plot follows the experiences of the three protagonists with the rising of the rebellion against the Society, the race to find the cure against a plague of mysterious origin, and discovering the real intentions of the Rising. 　Critical reception of the novel was positive and it reached No. 6 on USA Today's Best Selling Books list in 2012.

Official

An official is someone who holds an office (function or mandate, regardless of whether it carries an actual working space with it) in an organization or government and participates in the exercise of authority (either their own or that of their superior and/or employer, public or legally private). 　An elected official is a person who is an official by virtue of an election. 　Officials may also be appointed ex officio (by virtue of another office, often in a specified capacity, such as presiding, advisory, secretary). 　Some official positions may be inherited. 　A person who currently holds an office is referred to as an incumbent. 　Something "official" refers to something endowed with governmental or other authoritative recognition or mandate, as in official language, official gazette, or official scorer.

Fact

A fact is a datum about one or more aspects of a circumstance, which, if accepted as true and proven true, allows a logical conclusion to be reached on a true–false evaluation. 　Standard reference works are often used to check facts. 　Scientific facts are verified by repeatable careful observation or measurement by experiments or other means. 　For example, "This sentence contains words." accurately describes a linguistic fact, and "The sun is a star" accurately describes an astronomical fact. 　Further, "Abraham Lincoln was the 16th President of the United States" and "Abraham Lincoln was assassinated" both accurately describe historical facts. 　Generally speaking, facts are independent of belief and of knowledge and opinion. 　Facts are different from theories, values, and objects.

Sound

Drum - Cadence A Drum cadences performed by the United States Navy Band Problems playing this file? 　See media help. 　In physics, sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid. 　In human physiology and psychology, sound is the reception of such waves and their perception by the brain. 　Only acoustic waves that have frequencies lying between about 20 Hz and 20 kHz, the audio frequency range, elicit an auditory percept in humans. 　In air at atmospheric pressure, these represent sound waves with wavelengths of 17 meters (56 ft) to 1.7 centimeters (0.67 in). 　Sound waves above 20 kHz are known as ultrasound and are not audible to humans. 　Sound waves below 20 Hz are known as infrasound. 　Different animal species have varying hearing ranges.

Battle

A battle is an occurrence of combat in warfare between opposing military units of any number or size. 　A war usually consists of multiple battles. 　In general, a battle is a military engagement that is well defined in duration, area, and force commitment. 　An engagement with only limited commitment between the forces and without decisive results is sometimes called a skirmish. 　The word "battle" can also be used infrequently to refer to an entire operational campaign, although this usage greatly diverges from its conventional or customary meaning. 　Generally, the word "battle" is used for such campaigns if referring to a protracted combat encounter in which either one or both of the combatants had the same methods, resources, and strategic objectives throughout the encounter. 　Some prominent examples of this would be the Battle of the Atlantic, Battle of Britain, and Battle of Stalingrad, all in World War II. 　Wars and military campaigns are guided by military strategy, whereas battles take place on a level of planning and execution known as operational mobility. 　German strategist Carl von Clausewitz stated that "the employment of battles ... to achieve the object of war" was the essence of strategy.

Museum

A museum (/mjuːˈziːəm/ mew-ZEE-əm; plural museums or, rarely, musea) is a building or institution that cares for and displays a collection of artifacts and other objects of artistic, cultural, historical, or scientific importance. 　Many public museums make these items available for public viewing through exhibits that may be permanent or temporary. 　The largest museums are located in major cities throughout the world, while thousands of local museums exist in smaller cities, towns, and rural areas. 　Museums have varying aims, ranging from the conservation and documentation of their collection, serving researchers and specialists, to catering to the general public. 　The goal of serving researchers is not only scientific, but intended to serve the general public. 　There are many types of museums, including art museums, natural history museums, science museums, war museums, and children's museums. 　According to the International Council of Museums (ICOM), there are more than 55,000 museums in 202 countries.

Addition

Addition (usually signified by the plus symbol +) is one of the four basic operations of arithmetic, the other three being subtraction, multiplication and division. 　The addition of two whole numbers results in the total amount or sum of those values combined. 　The example in the adjacent image shows a combination of three apples and two apples, making a total of five apples. 　This observation is equivalent to the mathematical expression "3 + 2 = 5" (that is, "3 plus 2 is equal to 5"). 　Besides counting items, addition can also be defined and executed without referring to concrete objects, using abstractions called numbers instead, such as integers, real numbers and complex numbers. 　Addition belongs to arithmetic, a branch of mathematics. 　In algebra, another area of mathematics, addition can also be performed on abstract objects such as vectors, matrices, subspaces and subgroups. 　Addition has several important properties. 　It is commutative, meaning that the order of the operands does not matter, and it is associative, meaning that when one adds more than two numbers, the order in which addition is performed does not matter (see Summation). 　Repeated addition of 1 is the same as counting (see Successor function). 　Addition of 0 does not change a number. 　Addition also obeys predictable rules concerning related operations such as subtraction and multiplication. 　Performing addition is one of the simplest numerical tasks to do. 　Addition of very small numbers is accessible to toddlers; the most basic task, 1 + 1, can be performed by infants as young as five months, and even some members of other animal species. 　In primary education, students are taught to add numbers in the decimal system, starting with single digits and progressively tackling more difficult problems. 　Mechanical aids range from the ancient abacus to the modern computer, where research on the most efficient implementations of addition continues to this day.

India

India, officially the Republic of India (Hindi: Bhārat Gaṇarājya), is a country in South Asia. 　It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. 　Bounded by the Indian Ocean on the south, the Arabian Sea on the southwest, and the Bay of Bengal on the southeast, it shares land borders with Pakistan to the west; China, Nepal, and Bhutan to the north; and Bangladesh and Myanmar to the east. 　In the Indian Ocean, India is in the vicinity of Sri Lanka and the Maldives; its Andaman and Nicobar Islands share a maritime border with Thailand, Myanmar, and Indonesia. 　Modern humans arrived on the Indian subcontinent from Africa no later than 55,000 years ago. 　Their long occupation, initially in varying forms of isolation as hunter-gatherers, has made the region highly diverse, second only to Africa in human genetic diversity. 　Settled life emerged on the subcontinent in the western margins of the Indus river basin 9,000 years ago, evolving gradually into the Indus Valley Civilisation of the third millennium BCE. 　By 1200 BCE, an archaic form of Sanskrit, an Indo-European language, had diffused into India from the northwest. 　Its evidence today is found in the hymns of the Rigveda. 　Preserved by a resolutely vigilant oral tradition, the Rigveda records the dawning of Hinduism in India. 　The Dravidian languages of India were supplanted in the northern and western regions. 　By 400 BCE, stratification and exclusion by caste had emerged within Hinduism, and Buddhism and Jainism had arisen, proclaiming social orders unlinked to heredity. 　Early political consolidations gave rise to the loose-knit Maurya and Gupta Empires based in the Ganges Basin. 　Their collective era was suffused with wide-ranging creativity, but also marked by the declining status of women, and the incorporation of untouchability into an organised system of belief. 　In South India, the Middle kingdoms exported Dravidian-languages scripts and religious cultures to the kingdoms of Southeast Asia. 　In the early medieval era, Christianity, Islam, Judaism, and Zoroastrianism became established on India's southern and western coasts. 　Muslim armies from Central Asia intermittently overran India's northern plains, eventually founding the Delhi Sultanate, and drawing northern India into the cosmopolitan networks of medieval Islam. 　In the 15th century, the Vijayanagara Empire created a long-lasting composite Hindu culture in south India. 　In the Punjab, Sikhism emerged, rejecting institutionalised religion. 　The Mughal Empire, in 1526, ushered in two centuries of relative peace, leaving a legacy of luminous architecture. 　Gradually expanding rule of the British East India Company followed, turning India into a colonial economy, but also consolidating its sovereignty. 　British Crown rule began in 1858. 　The rights promised to Indians were granted slowly, but technological changes were introduced, and modern ideas of education and the public life took root. 　A pioneering and influential nationalist movement led by Mahatma Gandhi emerged, which was noted for nonviolent resistance and it became the major factor in ending British rule. 　In 1947 the British Indian Empire was partitioned into two independent dominions, a Hindu-majority Dominion of India and a Muslim-majority Dominion of Pakistan, amid large-scale loss of life and an unprecedented migration. 　India has been a federal republic since 1950, governed through a democratic parliamentary system. 　It is a pluralistic, multilingual and multi-ethnic society. 　India's population grew from 361 million in 1951 to almost 1.4 billion in 2022. 　During the same time, its nominal per capita income increased from US$64 annually to US$1,498, and its literacy rate from 16.6% to 74%. 　From being a comparatively destitute country in 1951, India has become a fast-growing major economy and a hub for information technology services, with an expanding middle class. 　It has a space programme which includes several planned or completed extraterrestrial missions. 　Indian movies, music, and spiritual teachings play an increasing role in global culture. 　India has substantially reduced its rate of poverty, though at the cost of increasing economic inequality. 　India is a nuclear-weapon state, which ranks high in military expenditure. 　It has disputes over Kashmir with its neighbours, Pakistan and China, unresolved since the mid-20th century. 　Among the socio-economic challenges India faces are gender inequality, child malnutrition, and rising levels of air pollution. 　India's land is megadiverse, with four biodiversity hotspots. 　Its forest cover comprises 21.7% of its area. 　India's wildlife, which has traditionally been viewed with tolerance in India's culture, is supported among these forests, and elsewhere, in protected habitats.

Australia

Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. 　With an area of 7,617,930 square kilometres (2,941,300 sq mi), Australia is the largest country by area in Oceania and the world's sixth-largest country. 　Australia is the oldest, flattest, and driest inhabited continent, with the least fertile soils. 　It is a megadiverse country, and its size gives it a wide variety of landscapes and climates, with deserts in the centre, tropical rainforests in the north-east, and mountain ranges in the south-east. 　The ancestors of Aboriginal Australians began arriving from south east Asia approximately 65,000 years ago, during the last ice age. 　Arriving by sea, they settled the continent and had formed approximately 250 distinct language groups by the time of European settlement, maintaining some of the longest known continuing artistic and religious traditions in the world. 　Australia's written history commenced with the European maritime exploration of Australia. 　The Dutch navigator Willem Janszoon was the first known European to reach Australia, in 1606. 　In 1770, the British explorer James Cook mapped and claimed the east coast of Australia for Great Britain, and the First Fleet of British ships arrived at Sydney in 1788 to establish the penal colony of New South Wales. 　The European population grew in subsequent decades, and by the end of the 1850s gold rush, most of the continent had been explored by European settlers and an additional five self-governing British colonies established. 　Democratic parliaments were gradually established through the 19th century, culminating with a vote for the federation of the six colonies and foundation of the Commonwealth of Australia on 1 January 1901. 　Australia has since maintained a stable liberal democratic political system and wealthy market economy. 　Politically, Australia is a federal parliamentary constitutional monarchy, comprising six states and ten territories. 　Australia's population of nearly 26 million is highly urbanised and heavily concentrated on the eastern seaboard. 　Canberra is the nation's capital, while its most populous city and financial centre is Sydney. 　The next four largest cities are Melbourne, Brisbane, Perth, and Adelaide. 　Australia's demography has been shaped by centuries of immigration: immigrants account for 30% of the country's population, and almost half of Australians have at least one parent born overseas. 　Australia's abundant natural resources and well-developed international trade relations are crucial to the country's economy, which generates its income from various sources including services, mining exports, banking, manufacturing, agriculture and international education. 　Australia is a highly developed country with a high-income economy. 　As of 2022, it was the world's fourteenth-largest economy with the ninth-highest per capita income. 　In 2021, it ranked as fifth-highest Human Development Index. 　Australia is a regional power, and has the world's thirteenth-highest military expenditure. 　Australia ranks amongst the highest in the world for quality of life, democracy, health, education, economic freedom, civil liberties, safety, and political rights, with all its major cities faring exceptionally in global comparative livability surveys. 　It is a member of international groupings including the United Nations, the G20, the OECD, the World Trade Organization, Asia-Pacific Economic Cooperation, the Pacific Islands Forum, the Pacific Community the Commonwealth of Nations, and the defence/security organisations ANZUS, AUKUS, the Five Eyes and the Quadrilateral Security Dialogue.

Matter

In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. 　All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic particles, and in everyday as well as scientific usage, "matter" generally includes atoms and anything made up of them, and any particles (or combination of particles) that act as if they have both rest mass and volume. 　However it does not include massless particles such as photons, or other energy phenomena or waves such as light or heat.　: 21  Matter exists in various states (also known as phases). 　These include classical everyday phases such as solid, liquid, and gas – for example water exists as ice, liquid water, and gaseous steam – but other states are possible, including plasma, Bose–Einstein condensates, fermionic condensates, and quark–gluon plasma. 　Usually atoms can be imagined as a nucleus of protons and neutrons, and a surrounding "cloud" of orbiting electrons which "take up space". 　However this is only somewhat correct, because subatomic particles and their properties are governed by their quantum nature, which means they do not act as everyday objects appear to act – they can act like waves as well as particles and they do not have well-defined sizes or positions. 　In the Standard Model of particle physics, matter is not a fundamental concept because the elementary constituents of atoms are quantum entities which do not have an inherent "size" or "volume" in any everyday sense of the word. 　Due to the exclusion principle and other fundamental interactions, some "point particles" known as fermions (quarks, leptons), and many composites and atoms, are effectively forced to keep a distance from other particles under everyday conditions; this creates the property of matter which appears to us as matter taking up space. 　For much of the history of the natural sciences people have contemplated the exact nature of matter. 　The idea that matter was built of discrete building blocks, the so-called particulate theory of matter, appeared in both ancient Greece and ancient India. 　Early philosophers who proposed the particulate theory of matter include Kanada (c. 6th–century BCE or after), Leucippus (~490 BCE), and Democritus (~470–380 BCE).

Mass

Mass is an intrinsic property of a body. 　It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. 　It was found that different atoms and different elementary particles, theoretically with the same amount of matter, have nonetheless different masses. 　Mass in modern physics has multiple definitions which are conceptually distinct, but physically equivalent. 　Mass can be experimentally defined as a measure of the body's inertia, meaning the resistance to acceleration (change of velocity) when a net force is applied. 　The object's mass also determines the strength of its gravitational attraction to other bodies. 　The SI base unit of mass is the kilogram (kg). 　In physics, mass is not the same as weight, even though mass is often determined by measuring the object's weight using a spring scale, rather than balance scale comparing it directly with known masses. 　An object on the Moon would weigh less than it does on Earth because of the lower gravity, but it would still have the same mass. 　This is because weight is a force, while mass is the property that (along with gravity) determines the strength of this force.

France

Coordinates: 47°N 2°E / 47°N 2°E / 47; 2 France (French: [fʁɑ̃s] ), officially the French Republic (French: République française [ʁepyblik frɑ̃sɛz]), is a country located primarily in Western Europe. 　It also includes overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans, giving it one of the largest discontiguous exclusive economic zones in the world. 　Its metropolitan area extends from the Rhine to the Atlantic Ocean and from the Mediterranean Sea to the English Channel and the North Sea; overseas territories include French Guiana in South America, Saint Pierre and Miquelon in the North Atlantic, the French West Indies, and many islands in Oceania and the Indian Ocean. 　Its eighteen integral regions (five of which are overseas) span a combined area of 643,801 km2 (248,573 sq mi) and had a total population of over 68 million as of January 2023[update]. 　France is a unitary semi-presidential republic with its capital in Paris, the country's largest city and main cultural and commercial centre; other major urban areas include Marseille, Lyon, Toulouse, Lille, Bordeaux, and Nice. 　Inhabited since the Palaeolithic era, the territory of Metropolitan France was settled by Celtic tribes known as Gauls during the Iron Age. 　Rome annexed the area in 51 BC, leading to a distinct Gallo-Roman culture that laid the foundation of the French language. 　The Germanic Franks formed the Kingdom of Francia, which became the heartland of the Carolingian Empire. 　The Treaty of Verdun of 843 partitioned the empire, with West Francia becoming the Kingdom of France in 987. 　In the High Middle Ages, France was a powerful but highly decentralised feudal kingdom. 　Philip II successfully strengthened royal power and defeated his rivals to double the size of the crown lands; by the end of his reign, France had emerged as the most powerful state in Europe. 　From the mid-14th to the mid-15th century, France was plunged into a series of dynastic conflicts involving England, collectively known as the Hundred Years' War, and a distinct French identity emerged as a result. 　The French Renaissance saw art and culture flourish, conflict with the House of Habsburg, and the establishment of a global colonial empire, which by the 20th century would become the second-largest in the world. 　The second half of the 16th century was dominated by religious civil wars between Catholics and Huguenots that severely weakened the country. 　France again emerged as Europe's dominant power in the 17th century under Louis XIV following the Thirty Years' War. 　Inadequate economic policies, inequitable taxes and frequent wars (notably a defeat in the Seven Years' War and costly involvement in the American War of Independence) left the kingdom in a precarious economic situation by the end of the 18th century. 　This precipitated the French Revolution of 1789, which overthrew the Ancien Régime and produced the Declaration of the Rights of Man, which expresses the nation's ideals to this day. 　France reached its political and military zenith in the early 19th century under Napoleon Bonaparte, subjugating much of continental Europe and establishing the First French Empire. 　The French Revolutionary and Napoleonic Wars shaped the course of European and world history. 　The collapse of the empire initiated a period of relative decline, in which France endured a tumultuous succession of governments until the founding of the French Third Republic during the Franco-Prussian War in 1870. 　Subsequent decades saw a period of optimism, cultural and scientific flourishing, as well as economic prosperity, known as the Belle Époque. 　France was one of the major participants of World War I, from which it emerged victorious at a great human and economic cost. 　It was among the Allied powers of World War II but was soon occupied by the Axis in 1940. 　Following liberation in 1944, the short-lived Fourth Republic was established and later dissolved in the course of the Algerian War. 　The current Fifth Republic was formed in 1958 by Charles de Gaulle. 　Algeria and most French colonies became independent in the 1960s, with the majority retaining close economic and military ties with France. 　France retains its centuries-long status as a global centre of art, science and philosophy. 　It hosts the fifth-largest number of UNESCO World Heritage Sites and is the world's leading tourist destination, receiving over 89 million foreign visitors in 2018. 　France is a developed country ranked 28th in the Human Development Index, with the world's seventh-largest economy by nominal GDP and tenth-largest by PPP; in terms of aggregate household wealth, it ranks fourth in the world. 　France performs well in international rankings of education, health care, and life expectancy. 　It remains a great power in global affairs, being one of the five permanent members of the United Nations Security Council and an official nuclear-weapon state. 　France is a founding and leading member of the European Union and the Eurozone, as well as a key member of the Group of Seven, North Atlantic Treaty Organization (NATO), Organisation for Economic Co-operation and Development (OECD) and Francophonie.

Video

Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. 　Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) systems which, in turn, were replaced by flat panel displays of several types. 　Video systems vary in display resolution, aspect ratio, refresh rate, color capabilities and other qualities. 　Analog and digital variants exist and can be carried on a variety of media, including radio broadcast, magnetic tape, optical discs, computer files, and network streaming.

California

California is a state in the Western United States, located along the Pacific Coast. 　With nearly 39.2 million residents across a total area of approximately 163,696 square miles (423,970 km2), it is the most populous U.S. state and the third-largest by area. 　It is also the most populated subnational entity in North America and the 34th most populous in the world. 　The Greater Los Angeles and San Francisco Bay areas are the nation's second and fifth most populous urban regions respectively, with the former having more than 18.7 million residents and the latter having over 9.6 million. 　Sacramento is the state's capital, while Los Angeles is the most populous city in the state and the second most populous city in the country. 　San Francisco is the second most densely populated major city in the country. 　Los Angeles County is the country's most populous, while San Bernardino County is the largest county by area in the country. 　California borders Oregon to the north, Nevada and Arizona to the east, the Mexican state of Baja California to the south; and has a coastline along the Pacific Ocean to the west. 　The economy of the state of California is the largest in the United States, with a $3.4 trillion gross state product (GSP) as of 2022[update]. 　It is the largest sub-national economy in the world. 　If California were a sovereign nation, it would rank as the world's fifth-largest economy as of 2022[update], behind Germany and ahead of India, as well as the 37th most populous. 　The Greater Los Angeles area and the San Francisco Bay Area are the nation's second- and third-largest urban economies ($1.0 trillion and $0.5 trillion respectively as of 2020[update]). 　The San Francisco Bay Area Combined Statistical Area had the nation's highest gross domestic product per capita ($106,757) among large primary statistical areas in 2018, and is home to five of the world's ten largest companies by market capitalization and four of the world's ten richest people. 　Slightly over 84 percent of the state's residents hold a high school degree, the lowest high school education rate of all 50 states. 　Prior to European colonization, California was one of the most culturally and linguistically diverse areas in pre-Columbian North America and contained the highest Native American population density north of what is now Mexico. 　European exploration in the 16th and 17th centuries led to the colonization of California by the Spanish Empire. 　In 1804, it was included in Alta California province within the Viceroyalty of New Spain. 　The area became a part of Mexico in 1821, following its successful war for independence, but was ceded to the United States in 1848 after the Mexican–American War. 　The California Gold Rush started in 1848 and led to dramatic social and demographic changes, including large-scale immigration into California, a worldwide economic boom, and the California genocide of indigenous peoples. 　The western portion of Alta California was then organized and admitted as the 31st state on September 9, 1850, following the Compromise of 1850. 　Notable contributions to popular culture, for example in entertainment, sports, music, and fashion, have their origins in California. 　The state also has made noteworthy contributions in the fields of communication, information, innovation, education, environmentalism, economics, politics, technology, and religion. 　It is the home of Hollywood, the oldest and one of the largest film industries in the world, which has had a profound influence upon global entertainment. 　It is considered the origin of the American film industry, hippie counterculture, beach and car culture, the personal computer, the internet, fast food, diners, burger joints, skateboarding, and the fortune cookie among other innovations. 　The San Francisco Bay Area and the Greater Los Angeles Area are widely seen as the centers of the global technology and film industries, respectively. 　California's economy is very diverse: 58% of it is based on finance, government, real estate, technology, professional, scientific, technical and business services, education, health, transportation, trade, hospitality, leisure, utilities, tourism, manufacturing, construction, shipping, and many other industries. 　Although agriculture accounts for only 1.5% of the state's economy, California's agriculture industry has the highest output of any U.S. state. 　California's ports and harbors handle about a third of all U.S. imports, most originating in Pacific Rim international trade. 　The state's extremely diverse geography ranges from the Pacific Coast and metropolitan areas in the west to the Sierra Nevada mountains in the east, and from the redwood and Douglas fir forests in the northwest to the Mojave Desert in the southeast. 　The Central Valley, a major agricultural area, dominates the state's center. 　California is well known for its warm Mediterranean climate and monsoon seasonal weather. 　The large size of the state results in climates that vary from moist temperate rainforest in the north to arid desert in the interior, as well as snowy alpine in the mountains. 　Drought and wildfires are a persistent issue for the state. 　California has established a state program in recognition of Native American use of fire in ecosystems to mitigate wildfires.

Construction

Construction is a general term meaning the art and science to form objects, systems, or organizations, and comes from Latin constructio (from com- "together" and struere "to pile up") and Old French construction. 　To construct is the verb: the act of building, and the noun is construction: how something is built, the nature of its structure. 　In its most widely used context, construction covers the processes involved in delivering buildings, infrastructure, industrial facilities and associated activities through to the end of their life. 　It typically starts with planning, financing, and design, and continues until the asset is built and ready for use; construction also covers repairs and maintenance work, any works to expand, extend and improve the asset, and its eventual demolition, dismantling or decommissioning. 　The construction industry contributes significantly to many countries’ gross domestic products (GDP). 　Global expenditure on construction activities was about $4 trillion in 2012. 　In 2022, expenditure on the construction industry exceeded $11 trillion a year, equivalent to about 13 percent of global GDP. 　This spending was forecast to rise to around $14.8 trillion in 2030. 　Although the construction industry promotes economic development and brings many non-monetary benefits to many countries, it is one of the most hazardous industries. 　For example, about 20% (1,061) of US industry fatalities in 2019 happened in construction.

Post

Look up Post or post in Wiktionary, the free dictionary. 　Post or POST commonly refers to: Mail, the postal system, especially in Commonwealth of Nations countries An Post, the Irish national postal service Canada Post, Canadian postal service Deutsche Post, German postal service Iraqi Post, Iraqi postal service Russian Post, Russian postal service Hotel post, a service formerly offered by remote Swiss hotels for the carriage of mail to the nearest official post office United States Postal Service or USPS Parcel post, a postal service for mail that is heavier than ordinary letters Post, a job or occupation Post, POST, or posting may also refer to:

Sea

Sea refers to a large body of salty water, specifically of seawater. 　There are particular seas and the sea. 　The body of saline water that is generally referred to as the sea, is a body of salt water that extends as ocean water and ocean (or world ocean) over approximately 71% of the Earth's surface. 　The particular seas are either marginal seas, second-order sections of the oceanic sea (e.g. the Mediterranean Sea), or certain large, entirely landlocked, saltwater lakes (e.g. the Caspian Sea). 　The salinity of water bodies varies widely, being lower near the surface and the mouths of large rivers and higher in the depths of the ocean; however, the relative proportions of dissolved salts vary little across the oceans. 　The most abundant solid dissolved in seawater is sodium chloride. 　The water also contains salts of magnesium, calcium, potassium, and mercury, amongst many other elements, some in minute concentrations. 　The ocean moderates Earth's climate and has important roles in the water, carbon, and nitrogen cycles. 　The surface of water interacts with the atmosphere, exchanging properties such as particles and temperature, as well as currents. 　Surface currents are the water currents that are produced by the atmosphere's currents and its winds blowing over the surface of the water, producing wind waves, setting up through drag slow but stable circulations of water, as in the case of the ocean sustaining deep-sea ocean currents. 　Deep-sea currents, known together as the global conveyor belt, carry cold water from near the poles to every ocean and significantly influencing Earth's climate. 　Tides, the generally twice-daily rise and fall of sea levels, are caused by Earth's rotation and the gravitational effects of the Moon and, to a lesser extent, of the Sun. 　Tides may have a very high range in bays or estuaries. 　Submarine earthquakes arising from tectonic plate movements under the oceans can lead to destructive tsunamis, as can volcanoes, huge landslides, or the impact of large meteorites. 　A wide variety of organisms, including bacteria, protists, algae, plants, fungi, and animals, lives in the seas, which offers a wide range of marine habitats and ecosystems, ranging vertically from the sunlit surface and shoreline to the great depths and pressures of the cold, dark abyssal zone, and in latitude from the cold waters under polar ice caps to the warm waters of coral reefs in tropical regions. 　Many of the major groups of organisms evolved in the sea and life may have started there. 　The seas have been an integral element for humans throughout history and culture. 　Humans harnessing and studying the seas have been recorded since ancient times, and evidenced well into prehistory, while its modern scientific study is called oceanography and maritime space is governed by the law of the sea, with admiralty law regulating human interactions at sea. 　The seas provide substantial supplies of food for humans, mainly fish, but also shellfish, mammals and seaweed, whether caught by fishermen or farmed underwater. 　Other human uses of the seas include trade, travel, mineral extraction, power generation, warfare, and leisure activities such as swimming, sailing, and scuba diving. 　Many of these activities create marine pollution.

Hair

Hair is a protein filament that grows from follicles found in the dermis. 　Hair is one of the defining characteristics of mammals. 　The human body, apart from areas of glabrous skin, is covered in follicles which produce thick terminal and fine vellus hair. 　Most common interest in hair is focused on hair growth, hair types, and hair care, but hair is also an important biomaterial primarily composed of protein, notably alpha-keratin. 　Attitudes towards different forms of hair, such as hairstyles and hair removal, vary widely across different cultures and historical periods, but it is often used to indicate a person's personal beliefs or social position, such as their age, sex, or religion.

Word

A word is a basic element of language that carries an objective or practical meaning, can be used on its own, and is uninterruptible. 　Despite the fact that language speakers often have an intuitive grasp of what a word is, there is no consensus among linguists on its definition and numerous attempts to find specific criteria of the concept remain controversial. 　Different standards have been proposed, depending on the theoretical background and descriptive context; these do not converge on a single definition.　: 13:618  Some specific definitions of the term "word" are employed to convey its different meanings at different levels of description, for example based on phonological, grammatical or orthographic basis. 　Others suggest that the concept is simply a convention used in everyday situations.　: 6  The concept of "word" is distinguished from that of a morpheme, which is the smallest unit of language that has a meaning, even if it cannot stand on its own. 　Words are made out of at least one morpheme. 　Morphemes can also be joined to create other words in a process of morphological derivation.　: 768  In English and many other languages, the morphemes that make up a word generally include at least one root (such as "rock", "god", "type", "writ", "can", "not") and possibly some affixes ("-s", "un-", "-ly", "-ness"). 　Words with more than one root ("[type][writ]er", "[cow][boy]s", "[tele][graph]ically") are called compound words. 　In turn, words are combined to form other elements of language, such as phrases ("a red rock", "put up with"), clauses ("I threw a rock"), and sentences ("I threw a rock, but missed"). 　In many languages, the notion of what constitutes a "word" may be learned as part of learning the writing system. 　This is the case for the English language, and for most languages that are written with alphabets derived from the ancient Latin or Greek alphabets. 　In English orthography, the letter sequences "rock", "god", "write", "with", "the", and "not" are considered to be single-morpheme words, whereas "rocks", "ungodliness", "typewriter", and "cannot" are words composed of two or more morphemes ("rock"+"s", "un"+"god"+"li"+"ness", "type"+"writ"+"er", and "can"+"not").