Eyes are organs of the visual system. They provide animals with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and convert it into electro-chemical impulses in neurons. In higher organisms, the eye is a complex optical system which collects light from the surrounding environment, regulates its intensity through a diaphragm, focuses it through an adjustable assembly of lenses to form an image, converts this image into a set of electrical signals, and transmits these signals to the brain through complex neural pathways that connect the eye via the optic nerve to the visual cortex and other areas of the brain. Eyes with resolving power have come in ten fundamentally different forms, and 96% of animal species possess a complex optical system. Image-resolving eyes are present in molluscs, chordates and arthropods.The most simple eyes, pit eyes, are eye-spots which may be set into a pit to reduce the angles of light that enters and affects the eye-spot, to allow the organism to deduce the angle of incoming light. From more complex eyes, retinal photosensitive ganglion cells send signals along the retinohypothalamic tract to the suprachiasmatic nuclei to effect circadian adjustment and to the pretectal area to control the pupillary light reflex.


== Overview ==

Complex eyes can distinguish shapes and colours. The visual fields of many organisms, especially predators, involve large areas of binocular vision to improve depth perception. In other organisms, eyes are located so as to maximise the field of view, such as in rabbits and horses, which have monocular vision.

Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation.Other animal coverings, such as the arthropod exoskeleton, have different developmental origin, structure and chemical composition. The adjective cutaneous means "of the skin" (from Latin cutis 'skin'). In mammals, the skin is an organ of the integumentary system made up of multiple layers of ectodermal tissue, and guards the underlying muscles, bones, ligaments and internal organs. Skin of a different nature exists in amphibians, reptiles, and birds. All mammals have some hair on their skin, even marine mammals like whales, dolphins, and porpoises which appear to be hairless.
The skin interfaces with the environment and is the first line of defense from external factors. For example, the skin plays a key role in protecting the body against pathogens and excessive water loss. Its other functions are insulation, temperature regulation, sensation, and the production of vitamin D folates.  Severely damaged skin may heal by forming scar tissue. This is sometimes discoloured and depigmented.

Skin

The Mona Lisa (; italian: La Gioconda [la dʒoˈkonda] or Monna Lisa [ˈmɔnna ˈliːza]) is a half-length portrait painting by Italian artist Leonardo da Vinci. Considered an archetypal masterpiece of the Italian Renaissance, it has been described as "the best known, the most visited, the most written about, the most sung about, the most parodied work of art in the world". The painting's novel qualities include the subject's enigmatic expression, the monumentality of the composition, the subtle modelling of forms, and the atmospheric illusionism.The painting is probably of the Italian noblewoman Lisa Gherardini, the wife of Francesco del Giocondo, and is in oil on a white Lombardy poplar panel. Leonardo never gave the painting to the Giocondo family, and later it is believed he left it in his will to his favored apprentice Salaì. It had been believed to have been painted between 1503 and 1506; however, Leonardo may have continued working on it as late as 1517. It was acquired by King Francis I of France and is now the property of the French Republic itself, on permanent display at the Louvre, Paris since 1797.The Mona Lisa is one of the most valuable paintings in the world. It holds the Guinness World Record for the highest known insurance valuation in history at US$100 million in 1962 (equivalent to $660 million in 2019).


== Title and subject ==

The title of the painting, which is known in English as Mona Lisa, comes from a description by Renaissance art historian Giorgio Vasari, who wrote "Leonardo undertook to paint, for Francesco del Giocondo, the portrait of Mona Lisa, his wife." Mona in Italian is a polite form of address originating as ma donna – similar to Ma'am, Madam, or my lady in English. This became madonna, and its contraction mona. The title of the painting, though traditionally spelled Mona (as used by Vasari), is also commonly spelled in modern Italian as Monna Lisa (mona being a vulgarity in some Italian dialects), but this is rare in English.Vasari's account of the Mona Lisa comes from his biography of Leonardo published in 1550, 31 years after the artist's death.

Mona Lisa

Mona_Lisa

Pompeii (, Latin: [pɔmˈpei̯.iː]) was an ancient city located in what is now the comune of Pompei near Naples in the Campania region of Italy. Pompeii, along with Herculaneum and many villas in the surrounding area (e.g. at Boscoreale, Stabiae), was buried under 4 to 6 m (13 to 20 ft) of volcanic ash and pumice in the eruption of Mount Vesuvius in AD 79.
Largely preserved under the ash, the excavated city offered a unique snapshot of Roman life, frozen at the moment it was buried, and an extraordinarily detailed insight into the everyday life of its inhabitants, although much of the evidence was lost in the early excavations. It was a wealthy town, enjoying many fine public buildings and luxurious private houses with lavish decorations, furnishings and works of art which were the main attractions for the early excavators. Organic remains, including wooden objects and human bodies, were entombed in the ash. Over time, they decayed, leaving voids which archaeologists found could be used as moulds to make plaster casts of unique — and often gruesome — figures in their final moments of life. The numerous graffiti carved on the walls and inside rooms provide a wealth of examples of the largely lost Vulgar Latin spoken colloquially at the time, contrasting with the formal language of the classical writers.
Pompeii is a UNESCO World Heritage Site and is one of the most popular tourist attractions in Italy, with approximately 2.5 million visitors annually.After many excavations prior to 1960 that had uncovered most of the city but left it in decay, further major excavations were banned and instead they were limited to targeted, prioritised areas. In 2018, these led to new discoveries in some previously unexplored areas of the city.

Pompeii

Switzerland, officially the Swiss Confederation, is a landlocked country situated at the confluence of Western, Central, and Southern Europe. It is a federal republic composed of 26 cantons, with federal authorities based in Bern. Switzerland is bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. It is geographically divided among the Swiss Plateau, the Alps, and the Jura, spanning a total area of 41,285 km2 (15,940 sq mi), and land area of 39,997 km2 (15,443 sq mi). Although the Alps occupy the greater part of the territory, the Swiss population of approximately 8.5 million is concentrated mostly on the plateau, where the largest cities and economic centres are located, among them Zürich, Geneva, and Basel. These cities are home to several offices of international organisations such as the headquarters of FIFA, the UN's second-largest Office, and the main building of the Bank for International Settlements. The main international airports of Switzerland are also located in these cities.
The establishment of the Old Swiss Confederacy dates to the late medieval period, resulting from a series of military successes against Austria and Burgundy. Swiss independence from the Holy Roman Empire was formally recognized in the Peace of Westphalia in 1648. The Federal Charter of 1291 is considered the founding document of Switzerland which is celebrated on Swiss National Day.

Switzerland

Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorpha (or Selachii) and are the sister group to the rays. However, the term "shark" has also been used for extinct members of the subclass Elasmobranchii outside the Selachimorpha, such as Cladoselache and Xenacanthus, as well as other Chondrichthyes such as the holocephalid eugenedontidans.
Under this broader definition, the earliest known sharks date back to more than 420 million years ago. Acanthodians are often referred to as "spiny sharks"; though they are not part of Chondrichthyes proper, they are a paraphyletic assemblage leading to cartilaginous fish as a whole.  Since then, sharks have diversified into over 500 species. They range in size from the small dwarf lanternshark (Etmopterus perryi), a deep sea species of only 17 centimetres (6.7 in) in length, to the whale shark (Rhincodon typus), the largest fish in the world, which reaches approximately 12 metres (40 ft) in length. Sharks are found in all seas and are common to depths of 2,000 metres (6,600 ft). They generally do not live in freshwater although there are a few known exceptions, such as the bull shark and the river shark, which can be found in both seawater and freshwater. Sharks have a covering of dermal denticles that protects their skin from damage and parasites in addition to improving their fluid dynamics.

Shark

Beefalo constitute a fertile hybrid offspring of domestic cattle (Bos taurus), usually a male in managed breeding programs, and the American bison (Bison bison), usually a female in managed breeding programs. The breed was created to combine the characteristics of both animals for beef production.
Beefalo are primarily cattle in genetics and appearance, with the breed association defining a full Beefalo as one with three-eighths (37.5%) bison genetics, while animals with higher percentages of bison genetics are called "bison hybrids".


== History ==
Accidental crosses were noticed as long ago as 1749 in the Southern states of North America, during British colonization. Cattle and bison were first intentionally crossbred during the mid-19th century.The first deliberate attempts to cross breed bison with cattle was made by Colonel Samuel Bedson, warden of Stoney Mountain Penitentiary, Winnipeg, in 1880. Bedson bought eight bison from a captive herd of James McKay and inter-bred them with Durham cattle. The hybrids raised by Bedson were described by naturalist Ernest Thompson Seton:
The hybrid animal is [claimed] to be a great improvement on both of its progenitors, as it is more docile and a better milker than the Buffalo, but retains its hardihood, while the robe is finer, darker and more even, and the general shape of the animal is improved by the reduction of the hump and increased proportion of the hind-quarters.
After seeing thousands of cattle die in a Kansas blizzard in 1886, Charles "Buffalo" Jones, a co-founder of Garden City, Kansas, also worked to cross bison and cattle at a ranch near the future Grand Canyon National Park, with the hope the animals could survive the harsh winters.  He called the result "cattalo" in 1888. Mossom Martin Boyd of Bobcaygeon, Ontario first started the practice in Canada, publishing about some of his outcomes in the Journal of Heredity.

Beefalo

Idaho ( (listen)) is a state in the Pacific Northwest region of the United States. It borders the state of Montana to the east and northeast, Wyoming to the east, Nevada and Utah to the south, and Washington and Oregon to the west. To the north, it shares a small portion of the Canadian border with the province of British Columbia. With a population of approximately 1.8 million and an area of 83,570 square miles (216,400 km2), Idaho is the 14th largest, the 13th least populous and the 7th least densely populated of the 50 U.S. states. The state's capital and largest city is Boise.
For thousands of years Idaho has been inhabited by Native American peoples. In the early 19th century, Idaho was considered part of the Oregon Country, an area disputed between the United States and the British Empire. It officially became U.S. territory with the signing of the Oregon Treaty of 1846, but a separate Idaho Territory was not organized until 1863, instead being included for periods in Oregon Territory and Washington Territory. Idaho was eventually admitted to the Union on July 3, 1890, becoming the 43rd state.
Forming part of the Pacific Northwest (and the associated Cascadia bioregion), Idaho is divided into several distinct geographic and climatic regions.

Idaho

Penguins (order Sphenisciformes , family Spheniscidae ) are a group of aquatic flightless birds. They live almost exclusively in the Southern Hemisphere, with only one species, the Galápagos penguin, found north of the Equator. Highly adapted for life in the water, penguins have countershaded dark and white plumage and flippers for swimming. Most penguins feed on krill, fish, squid and other forms of sea life which they catch while swimming underwater. They spend roughly half of their lives on land and the other half in the sea.
Although almost all penguin species are native to the Southern Hemisphere, they are not found only in cold climates, such as Antarctica. In fact, only a few species of penguin live so far south. Several species are found in the temperate zone, but one species, the Galápagos penguin, lives near the Equator.
The largest living species is the emperor penguin (Aptenodytes forsteri): on average, adults are about 1.1 m (3 ft 7 in) tall and weigh 35 kg (77 lb). The smallest penguin species is the little blue penguin (Eudyptula minor), also known as the fairy penguin, which stands around 33 cm (13 in) tall and weighs 1 kg (2.2 lb).

Penguin

Cattle, or cows (female) and bulls (male), are large domesticated cloven-hooved herbivores. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos taurus. 
Cattle are commonly raised as livestock for meat (beef or veal, see beef cattle), for milk (see dairy cattle), and for hides, which are used to make leather. They are used as riding animals and draft animals (oxen or bullocks, which pull carts, plows and other implements). Another product of cattle is their dung, which can be used to create manure or fuel. In some regions, such as parts of India, cattle have significant religious meaning. Cattle, mostly small breeds such as the Miniature Zebu, are also kept as pets.
Around 10,500 years ago, taurine cattle were domesticated from as few as 80 progenitors in central Anatolia, the Levant and Western Iran. According to the Food and Agriculture Organization (FAO), there are approximately 1.5 billion cattle in the world as of 2018. In 2009, cattle became one of the first livestock animals to have a fully mapped genome.

Cattle

Philadelphia, colloquially Philly, is a city in the state of Pennsylvania in the United States. It is the sixth-most-populous city in the United States and the most populous city in the state of Pennsylvania, with a 2019 estimated population of 1,584,064. It is also the second-most populous city in the Northeastern United States, behind New York City. Since 1854, the city has had the same geographic boundaries as Philadelphia County, the most-populous county in Pennsylvania and the urban core of the eighth-largest U.S. metropolitan statistical area, with over 6 million residents as of 2017. Philadelphia is also the economic and cultural center of the greater Delaware Valley along the lower Delaware and Schuylkill rivers within the Northeast megalopolis. The Delaware Valley's 2019 estimated population of 7.21 million makes it the ninth-largest combined statistical area in the United States.Philadelphia is one of the oldest municipalities in the United States. William Penn, an English Quaker, founded the city in 1682 to serve as capital of the Pennsylvania Colony. Philadelphia played an instrumental role in the American Revolution as a meeting place for the Founding Fathers of the United States, who signed the Declaration of Independence in 1776 at the Second Continental Congress, and the Constitution at the Philadelphia Convention of 1787. Several other key events occurred in Philadelphia during the Revolutionary War including the First Continental Congress, the preservation of the Liberty Bell, the Battle of Germantown, and the Siege of Fort Mifflin. Philadelphia remained the nation's largest city until being overtaken by New York City in 1790; the city was also one of the nation's capitals during the revolution, serving as temporary U.S. capital while Washington, D.C. was under construction.

Philadelphia

A pig is any of the animals in the genus Sus, within the even-toed ungulate family Suidae. Pigs include domestic pigs and their ancestor, the common Eurasian wild boar (Sus scrofa), along with other species. Pigs, like all suids, are native to the Eurasian and African continents, ranging from Europe to the Pacific islands. Suids other than the pig are the babirusa of Indonesia, the pygmy hog of South Asia, the warthog of Africa, and other pig genera from Africa. The suids are a sister clade to peccaries.
Juvenile pigs are known as piglets. Pigs are highly social and intelligent animals.With around 1 billion individuals alive at any time, the domestic pig is among the most populous large mammals in the world. Pigs are omnivores and can consume a wide range of food. Pigs are biologically similar to humans and are thus frequently used for human medical research.


== Etymology ==
The Online Etymology Dictionary provides anecdotal evidence as well as linguistic, saying that the term derives

probably from Old English *picg, found in compounds, ultimate origin unknown.

Wiki's

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