Aarushhh/wikipedia-simple-splitted huggingface dataset:
0.999... (also written as 0. or 0., and read as "0 point 9 repeating") is one of the ways the number 1 (one) can be written. Even though it is written like this, no matter how many nines there are before the ellipsis, it is still equal in value to 1.

About 
0.999... is a repeating decimal, which means the digit "9" is repeated forever. It is different from 0.999, which only has three 9s.

0.999... can also be written as
 or
.

It is hard for many people to understand why 0.999... is the same as 1. There are many proofs that show why they are the same number, but many of these proofs are very complex.

Examples 
One simple way of showing that 0.999... and 1 are the same thing is to divide them both by the number 3. When 0.999... is divided by 3, the answer is 0.333..., which is the same as  (the fraction one third).
When 1 is divided by 3, the answer is . Since the answers are the same, that means that 0.999... and 1 are the same. Another way of thinking about it is if  and , then  therefore, as , 0.999... must also equal 1. There are many other ways of showing this.

Another way of proving that 0.999... = 1 is by accepting the simple fact that if two numbers are different, there must be at least one number between them. For example, a number between 1 and 2 is 1.5, and a number between 0.9 and 1 is 0.95. Since 0.999... has an infinite number of 9s, there cannot be another number after the "last" 9, meaning there is no number between 0.999... and 1. Therefore, they are equal.

One more common proof is such:
In popular culture 
As the Internet developed, arguments about 0.999... are often on newsgroups and message boards. Even newsgroups and message boards that do not have much to do with math argue about this. In the newsgroup sci.math, arguing about 0.999... is a "popular sport". It is also one of the questions in its FAQ.

Related pages 
 Limit (mathematics)

References

Other websites 
 Why does 0.9999... = 1?
 Ask A Scientist: Repeating Decimals 
 A Friendly Chat About Whether 0.999... = 1

Mathematics
Ophthalmosauridae were a family of Ichthyosaurs which lived from the Middle Jurassic to the Upper Cretaceous period.

Within Ophthalmosauridae there are two lineages, one including Aegirosaurus and Ophthalmosaurus, and the other including Brachypterygius, Caypullisaurus and Platypterygius.

Only three genera survived the end-Jurassic extinction event: Caypullisaurus, Maiaspondylus, and Platypterygius. They did, however, have a worldwide distribution. The last to survive was Platypterygius. This genus became extinct about 30 million years before the end of the Upper Cretaceous period. It happened when there was a deep ocean anoxic event, which wiped out all the animals below pelagic waters. Ichthyosaurs, being reptiles, came to the surface to breath, but the extinction event removed their prey species.

References

Ichthyosaurs
An anoxic event (AE) is an event in which parts of the ocean have become low in oxygen (O2) below the surface levels, or when all the oxygen has gone. They may be called oceanic anoxic events or deep ocean anoxic events.

Major anoxic events have happened, though not for millions of years. The geological record of organic-rich sediment (black shales) shows that they happened in the past. However, only "in rare, extreme cases, [did] euxinia lead to biotic crises. [The] hypothesis  [is] best supported by evidence from the end-Permian mass extinction".

Anoxic events may have caused mass extinctions. These mass extinctions were so characteristic that they have been used by geologists as markers in biostratigraphic dating. Typically, oceanic anoxic events last for under half a million years, before a full recovery.
There are several places on earth today that show the features of anoxic events on a localized level. 'Dead zones' exist off the East Coast of the United States in the Chesapeake Bay, in the Scandinavian strait Kattegat, the Black Sea, in the northern Adriatic and off the coast of Louisiana.

Events which may have caused anoxic events 
It is not known why anoxic events may have happened. Some ideas include:

Global warm climate leading to a huge growth of biomass.
High rainfall sweeping organic material down into the oceans.
Deep water circulation between poles and the equator stopping.
Oceanic oxygen being used up, and not being replaced fast enough.
Poisonous hydrogen sulphide collecting in the oceans.
Oceans becoming hostile to most forms of life

All of these events may have caused mass extinction in the seas, changing ways in which all animals which feed on sea creatures.

Historic examples

Jurassic 	
Toarcian event 183 million years ago (mya)
Lower Cretaceous 
Aptian: mid-Aptian extinction event, 116/7 mya.

Upper Cretaceous 
Cenomanian–Turonian boundary event: black shale deposition in ocean basins. 91.5 (±8.6) mya.

Cainozoic 	
Palaeocene–Eocene Thermal Maximum (PETM), 55.8 mya.

References 

Extinction events
Oceanography
Metriacanthosaurus is a genus of theropod dinosaur that lived in Europe during the Middle Jurassic period, about 160 million years ago. Its name means "Moderate-spined lizard", because its back vertebrae are taller than other meat-eating dinosaurs such as Allosaurus, but shorter than those of other meat-eating dinosaurs, such as Acrocanthosaurus. Like most theropods, Metriacanthosaurus was a meat-eater. It had three fingers on each hand. Each finger ended in a sharp, hook-like claw that was used to grab prey before giving the killing bite with its jaws. It probably preyed on the large, long-necked sauropods, such as Pelorosaurus, that lived in the same time and place as it. It was originally classified as a megalosaurid, but recent studies show that it belongs to its own family, the Metriacanthosauridae

In popular culture
In Jurassic Park, one of the vials of dinosaur DNA that Dennis Nedry steals is labeled Metriacanthosaurus.

Carnosaurs
Acrocanthosaurus was a genus of theropod dinosaur that lived in North America during the Lower Cretaceous period. Its name means "high-spined lizard." This refers to the spines on its vertebrae, which formed a sail or hump when the animal was alive.

Its classification is uncertain. It was originally classified as a spinosaur because the spines on its back looked like those of Spinosaurus. However, Acrocanthosaurus is now classified as a carnosaur. Most paleontologists believe that it was a carcharodontosaurid.

Acrocanthosaurus was 38 feet long, almost as large as Tyrannosaurus rex, and weighed about 6 or 7 short tons. It was the largest theropod in North America before the evolution of the tyrannosaurs.

Long, low ridges start at the nasal bones. They run along each side of the snout from the nostril back to the eye, and they continue onto the lacrimal bones. This is a characteristic feature of all allosaurids.
A famous trackway in Paluxy, Texas shows tracks of what might be an Acrocanthosaurus and its prey. While interesting and plausible, this hypothesis is difficult to prove, and other explanations exist.

In popular culture 
Acrocanthosaurus was featured in an episode of the television documentary Monsters Resurrected. It was depicted as the top predator in early Cretaceous North America. A juvenile was scared away from its kill by a pack of Deinonychus, and was forced to hunt more difficult prey, such as a Sauropelta.

References 

Carnosaurs
Cretaceous dinosaurs
A flood basalt or trap basalt is the result of a giant volcanic eruption or series of eruptions that coats large stretches of land or the ocean floor with basalt lava.

Flood basalts have covered areas as large as a continent in prehistory, creating great plateaus and mountain ranges.  Flood basalts have erupted at various times throughout Earth history. They are clear evidence that the Earth has periods of higher activity rather than being in a uniform steady state.

One explanation for flood basalts is that they are caused by the combination of continental rifting and its associated melting. Then a mantle plume produces vast quantities of a basaltic magma. These have a low viscosity, which is why they 'flood' rather than form taller volcanoes.
Flood basalts start at between 100 and 400 km depth, in the asthenosphere. To get a partial melting as large as that of the traps, expelling huge quantities of lava, it is necessary to have a large heat input. Such melting can take place near a hotspot, resulting in a mixture of magma from the depths of the hotspot with superficial magma produced by a mantle plume.

Lava plateaux 
A lava plateau is a flat, wide surface (plateau) that is formed when lava comes out of the ground and spreads out very quickly. The layers of lava can build up over time to form a lava plateau. Here are the general properties of lava plateaux:
They are very large areas of basaltic lava with a layered structure.
 Lava makes the plateau bigger, and higher, with each eruption.
 They tend to be flat.
 Mid-ocean ridge eruptions make large plains on the sea floor.
 The lava of these plateaux are thin and runny.
These plateaux may take millions of years to form.
Overtime a number of fissure eruptions in the same area can build up a high plateau.
Examples 
The Emeishan Traps in southwestern China, around Sichuan province, the Deccan Traps of central India, the Siberian Traps, and the Columbia River Plateau of western North America are four large regions covered by prehistoric flood basalts. The two largest flood basalt events in historic time have been at Eldgjá and Lakagigar, both in Iceland. The largest and best-preserved continental flood basalt terrain on Earth is part of the Mackenzie Large Igneous Province in Canada. The maria on the Moon are additional, even more extensive, flood basalts.  Flood basalts on the ocean floor produce oceanic plateaus.

The surface covered by one eruption can vary from around 200,000 km² (Karoo) to 1,500,000 km² (Siberian Traps).  The thickness can vary from 2000 metres (Deccan Traps) to 12,000 m (Lake Superior). These are smaller than the original volumes due to erosion.
Another example of a lava plateau is the Giant's Causeway, in County Antrim, Northern Ireland. This is was originally part of a great volcanic plateau called the Thulean Plateau.

References 

Volcanology
Plateaus
Monterrey is a city in northern Mexico.  It is the capital of the state Nuevo León.  It is the third largest city in Mexico. It has 2,056,538 people.

 
Capital cities in Mexico
The Siberian Traps form a large region of volcanic rock, known as a large igneous province, in the Russian region of Siberia. 

The large eruptions which formed the traps were one of the largest known volcanic events of the last 500 million years of Earth history. They continued for a million years and spanned the Permian-Triassic boundary, about 251 to 250 million years ago. It was the same time as the Permian–Triassic extinction event, which is estimated to have killed 90% of species existing at the time. The eruption of the Siberian Traps is a possible cause of this "Great Dying".

The term "traps" is derived from the Swedish word for stairs (trappa, or sometimes trapp), referring to the step-like hills forming the landscape of the region, which is typical of flood basalts.
Geographical extent 
Vast volumes of basaltic lava paved over a large expanse of primaeval Siberia in a flood basalt event. Today the area covered is about 2 million km² – roughly equal to western Europe in land area – and estimates of the original coverage are as high as 7 million km². The original volume of lava is estimated to range from 1 to 4 million km³.

Origin
The source of the Siberian Traps basalt was, probably, a mantle plume at the base of the crust which erupted through the Siberian craton (the oldest part of the Siberian continental plate). Helium isotope analysis from the basalts indicates a plume origin. The scientific debate continues. There is a minority controversial theory which argues that the traps were caused by a large asteroid impact.

The Great Dying
The Great Dying 

This massive eruptive event spanned the Permian-Triassic boundary, about 250 million years ago, and is widely cited as a cause of the Permian-Triassic extinction event.  This extinction event, also called the Great Dying, affected all life on Earth, and is estimated to have killed 90% of species living at the time. Life on land took 30 million years to recover from the environmental disruptions caused by the eruption of the Siberian Traps.
Siberian Traps and nickel 
The Siberian Traps are considered to have erupted through numerous vents over a period of a million years or more, probably east and south of Norilsk in Siberia. The giant Norilsk nickel-copper-palladium deposit formed within the magma flows in the main Siberian Traps. The presence of extensive tuff and pyroclastic deposits suggests that a number of large explosive eruptions occurred during or before the eruptions of basaltic lavas. The presence of silicic volcanic rocks such as rhyolite is also indicative of explosive eruptions.

Related pages 
Flood basalt
Deccan Traps

Other websites 
The Siberian Traps 
The Siberian Traps, by Richard Cowen
The Siberian Traps Large Igneous Province
Toxic Gases Caused World's Worst Extinction

References 

Extinction events
Flood basalts
Volcanic landforms
Volcanoes of Asia
Mountains of Russia
Siberia
Large igneous provinces
The College of Marin is a community college in Marin County, California, U.S.. It has one campus in Kentfield and another in Novato.

California Community Colleges
1926 establishments in the United States
1920s establishments in California
Tellurium(II) chloride, also known as tellurium dichloride, is a chemical compound. Its chemical formula is TeCl2. It contains tellurium in its +2 oxidation state. It also contains chloride ions.

Properties
Tellurium(II) chloride is a black solid. It absorbs water. It can be oxidized to tellurium(IV) chloride. It reacts with water.

Related pages
Tellurium(II) bromide
Tellurium(IV) bromide

Tellurium compounds
Chlorine compounds
Tellurous acid is a chemical compound. It is also an acid. Its chemical formula is H2TeO3. It contains hydrogen and tellurite ions. It can be made by reacting tellurium dioxide with water. It is not made as easily as telluric acid.

It is a weak oxidizing agent and a weak reducing agent. It easily turns back into tellurium dioxide and water. It is a weak acid. It reacts with bases to make tellurites.

Related pages
Telluric acid
Sodium tellurite
Acids
Tellurium compounds
Tellurium(IV) chloride, also known as tellurium tetrachloride, is a chemical compound. Its chemical formula is TeCl4. It contains tellurium in its +4 oxidation state. It also contains chloride ions.

Properties
Tellurium(IV) chloride is a pale yellow solid. It melts easily to a red liquid. It evaporates easily. It reacts with water to make tellurium dioxide and hydrochloric acid. It is toxic and corrosive.

Preparation
Tellurium(IV) chloride is made by reacting tellurium powder and chlorine.

Uses
It is used in making organic compounds.

Related pages
Selenium(IV) chloride
Tellurium(II) chloride

Tellurium compounds
Chlorine compounds
Tellurium chloride may refer to either of these chemical compounds:

Tellurium(II) chloride
Tellurium(IV) chloride
U.S. Route 78 is an east–west highway. It goes from Memphis, Tennessee to Charleston, South Carolina.

References

78
Kim Clijsters (; born 8 June 1983)is a Belgian retired tennis player. She used to be ranked as the World No. 1. On 22 August 2011 she was ranked third in the world.

References 

1983 births
Living people
Belgian Olympians
Female tennis players
World No. 1 tennis players
Belgian tennis players
U.S. Route 25 is a US highway in the east part of the United States of America. It goes from north to south. The road begins in Cincinnati, Ohio, at the Ohio River and ends in Brunswick, Georgia, close to the Atlantic Ocean.

References

25
Asheville is the county seat of Buncombe County, North Carolina. It is located where the Swannanoa River and the French Broad River meet. The population of Asheville was counted as 94,589 in 2020. Asheville is the largest city in the North Carolina mountains.

References

County seats in North Carolina
June Cleaver is a literary reference meaning "the perfect stay-at-home mom" referring to the mother in the U.S. television show Leave it to Beaver which was released from 1957 to 1963. Women writers viewing the show sometimes had difficulty living up to or agreeing with such a feminine mystique.  June Cleaver is often referred to in remarks justifying a messy home such as “June Cleaver made having a spotless house look so effortless . . .” The character was played by actress Barbara Billingsley, a lifelong resident of Los Angeles county, California, U.S.A.

References 

Slang
Television characters
Jack’ Tweed (born 9 June 1987) is a British television personality.

Tweed started his career as Jade Goody's partner. He became widely known in 2007 after being on Celebrity Big Brother UK. He caused controversy when he called housemate Shilpa Shetty a "cunt" and "Paki" and said that she should remove objects from the toilet with her teeth. After Celebrity Big Brother, Goody miscarried his child in 2007. He married her on 22 February 2009 and she died of cervical cancer a month later. He appeared in 2010 ITV2 programme The Only Way Is Essex. In 2010, he had a relationship with Chanelle Hayes.
Tweed has had several legal issues. These include an 18-month prison sentence in September 2008 for assault occasioning actual bodily harm for attacking a 16-year-old boy with a golf club in December 2006. In March 2009, he was found guilty of common assault for attacking a taxi driver in May 2008. He was tried for the rape of a 19-year-old woman in April 2010, but found not guilty. In January 2011 he punched a man, for which he was convicted of common assault in August 2011.

References 

1987 births
Living people
British people convicted of assault
Celebrity Big Brother contestants
Criminals from London
People acquitted of rape
People from the London Borough of Waltham Forest
Television personalities from London
In Euclidean plane geometry, a quadrilateral is a polygon with four edges (or sides) and four vertices (or corners). Sometimes, the term quadrangle is used (similar to the term "triangle"), while other times, the term tetragon is used (similar to pentagon, 5-sided polygon, and hexagon, 6-sided polygon). A quadrilateral with vertices , , ,  is sometimes written as .

The origin of the word quadrilateral is the two Latin words quadri, a variant of four, and latus, meaning "side".

Quadrilaterals can be either complex, also called crossed (self-intersecting), or simple (not self-intersecting). Simple quadrilaterals are either convex or concave.

All the sides of a quadrilateral are straight, and the interior angles of a quadrilateral add up to 360°.

This is a special case of the n-gon interior angle sum formula: (n − 2) × 180°.

All non-self-crossing quadrilaterals tile the plane, by repeated rotation around the midpoints of their edges.
There are 6 special kinds of quadrilaterals; square, rectangle, rhombus, parallelogram, kite, and trapezoid. Technically, squares, rectangles, and rhombuses are types of parallelograms.

Related pages 

 Cube
 Cuboid

References 

4
Yangchuanosaurus was a genus of theropod dinosaur from the Jurassic of China. It was a fairly typical carnosaur, with a large head, sharp, serrated teeth, and relatively short arms (though not as short as those of Tyrannosaurus). It was the largest predator in its part of the world. Yangchuanosaurus probably preyed on sauropods, such as Mamenchisaurus, or stegosaurs, such as Tuojiangosaurus.

There are two species. Y. zigongensis is from the Middle Jurassic, and Y. shangyouensis is from the Upper Jurassic. Specimens were collected from the Dashanpu Dinosaur Quarry of Zigong, Sichuan.

The Middle Jurassic Y. zigongensis is known from four incomplete specimens. There are two specimens of the Upper Jurassic Y. shangyouensis, which were at first put into separate species. Later analysis showed they were probably different ages or variations of the same species.
The first skull is 82 cm (2.7 ft) long, and its total body length about 8 m (26 ft). The other specimen was even larger. It had a skull length of 1.11 m (3.6 ft). It may have been up to 10.8 m (35.4 ft) long, and weighed as much as 3.4 metric tons (3.7 short tons). There was a bony knob on its nose and multiple hornlets and ridges, similar to Ceratosaurus. It had a massive tail that was about half its length.

References 

Carnosaurs
Jurassic dinosaurs
Pelorosaurus conybeari is the name given to a few sauropod dinosaur bones from the Lower Cretaceous period, about 138–112 million years ago. 

Bones of Pelorosaurus have been found in England and Portugal. It was a Brachiosaur, with front legs that were longer than its hind legs. 

The name has been challenged, and has been the subject of long-lasting dispute. Some palaeontologists prefer the name Cetiosaurus brevis.

The taxonomic status of Pelorosaurus is as a result very problematic. Technically, Cetiosaurus brevis is its type species. The position of Pelorosaurus is further undermined by the fact that several researchers hold that the genus is a nomen dubium ('doubtful name').

Pelorosaurus was one of the first dinosaurs described, and the naming procedures were not so well-developed at the time. Its life-style is assumed to be similar to other brachiosaurs, eating from the higher branches of tall conifer trees.

References 

Brachiosaurs
Pope Leo X (; 11 December 1475 – 1 December 1521), born Giovanni di Lorenzo de' Medici, was an Italian priest of the Roman Catholic Church and the 218th Pope from 1513 to his death in 1521.

Early life
Giovanni de Medici was born in Florence.  He was the second son of Lorenzo the Magnificent.

He studied theology and canon law at Pisa from 1489 to 1491.

Priest 
Six days after his election as pope in 1513, Medici was ordained as a priest.

Bishop 
Two days after his ordination and eight days after his election as pope in 1513, Medici was made a bishop.

Cardinal
At the age of 13, Pope Innocent VIII named Medici cardinal in 1489.

Pope
Cardinal Medici was elected pope on 9 March 1513. On the 15 March he was ordained priest, and he was consecrated as bishop on March 17. He was crowned Pope on 19 March at the age of 37.

Pope Leo was involved in Italian and European political disputes.

Leo was a patron of Michelangelo and Raphael.

Related pages 
 List of popes
List of popes from the Medici family

References
References

Other websites

 

  "Leo X", Encyclopædia Britannica, 1911
  Catholic Hierarchy, Pope Leo X
  Cardinals of the Holy Roman Church, Cardinal Medici 

Italian popes
People from Florence
House of Medici
1475 births
1521 deaths
A crumpet is a kind of flat, small round bread that is raised by yeast. They are about the same size as an English muffin. They are made in crumpet rings that are four inches wide and usually one inch deep. Crumpets are usually baked on a griddle and served toasted. A well-baked crumpet has a brown bottom and a spongey top that has many tiny holes. Crumpets are toasted whole, while English muffins are split and then toasted. After the baking, crumpets are spread with butter or cream and jam.

Definition 

The word of crumpet may come from the Middle English word crompid (cake), or curled (cake). Or it may come from the past participle of the Middle English verb crumpen, which means to curl up. It could also have come from crumb, crump, or crooked, all Old English. Crumpet is also used as British slang for a particularly sexually attractive woman. It Australian slang, it is part of the expression: "not worth a crumpet", meaning that somebody or something is useless.

History
History 

The first recipe for crumpets was long ago, referred to frequently as the "crompid cake" by many. The Oxford English Dictionary traced the history back to 1382.

The Oxford Companion to Food also says that the earliest published recipe for crumpets was by Elizabeth Raffald, in 1769. There, the "crompid cake" is mentioned as well with buckwheat griddle cakes so it is believed that there is a connection between crumpets and the buckwheat pancake.

Elizabeth Raffald mentions it in her book of The Experienced English Housekeeper. Her recipe is very similar to the modern crumpet recipe, especially in the baking, buttering, and serving.

References 

Breads
Edam is a type of Dutch cheese. It is named after the town that it comes from, Edam in the Netherlands. Edam cheese is pale yellow. It is often sold in round pieces, covered in red paraffin wax. Edam that is sold in the Netherlands (and not exported) does not usually have wax on it.

References

Dutch cheeses
Edam-Volendam
The Night Angel Trilogy is a series of fantasy novels written by Brent Weeks. The first book in the series, The Way of Shadows, was published in October 2008, and the third book, Beyond the Shadows, was published in December 2008.

Books
 The Way of Shadows
 Shadow's Edge
 Beyond the Shadows

References

American fantasy books
Series of books
2008 books
Taylor Chorney (born April 27, 1987) is a Canadian-born American professional ice hockey defenceman. He currently plays for the Pittsburgh Penguins of the National Hockey League (NHL). He has also played for the Edmonton Oilers and St. Louis Blues.

He was drafted by the Edmonton Oilers with the 36th overall pick in the 2005 NHL Entry Draft. He previously played at the University of North Dakota. He also was on Team USA at the 2006 World Junior Championships. Chorney represented the USA again in the 2007 World Juniors, where he was team captain. He made his NHL debut on April 10, 2009 against the Calgary Flames. He recorded his first NHL point in his first game of the 2009-10 season, by assisting one of Zack Stortini's two goals on October 12, 2009 on the road against the Nashville Predators.

His father, Marc, played 210 games in the NHL for the Pittsburgh Penguins and Los Angeles Kings.

On July 1, 2014, Chorney signed one-year, two-way contract with the Pittsburgh Penguins.

References

Other websites
Other websites

1987 births
American Hockey League players
American ice hockey defensemen
Canadian ice hockey defencemen
Chicago Wolves players
Edmonton Oilers players
Ice hockey people from Ontario
Living people
Oklahoma City Barons players
Peoria Rivermen (AHL) players
Pittsburgh Penguins players
Sportspeople from Thunder Bay
Springfield Falcons players
Wilkes-Barre/Scranton Penguins players
A homologous trait is any characteristic which is derived by evolution from a common ancestor. This is contrasted to analogous traits: similarities between organisms that were evolved separately. 

The term existed before 1859, but got its modern meaning after Darwin established the idea of common descent.p45
The pre-Darwinian naturalists Cuvier, Geoffroy and Richard Owen, also used the idea.

A homologous trait is often called a homologue (also spelled homolog). In genetics, the term "homologue" is used both to refer to a homologous protein, and to the gene (DNA sequence) encoding it.

Homology vs analogy 
According to Russell, we owe to Richard Owen the first clear distinction between homologous and analogous organs. Owen's definitions were:
Analogue: a part or organ in one animal which has the same function as another part or organ in a different animal.
Homologue: the same organ in different animals under every variety of form and function.
The distinction is made clear by examples such as the ear ossicles of mammals. These little bones have, in the course of several hundred million years of evolution, made their way from the gill covers of fish to the rear jaw bones of Synapsids to their present position in the ear of mammals. In the fossil record is evidence of this, and also in embryology. As the embryo develops, the cartilage hardens to form bone. Later in development, tiny bone structures break loose from the jaw and migrate to the inner ear area. The ear ossicles are homologous with the jaw bones and the gill covers, but not analogous.

This rather extraordinary story was first proposed in 1818 by Étienne Geoffroy Saint-Hilaire, who looked at fish and tried to discover the homologies of their bones with that of land vertebrates.

Level of analysis
Level of analysis 

A trait may be both homologous and analogous, depending on the level at which the trait is examined. For example, the wings of birds and bats are homologous as forearms in tetrapods. However, they are not homologous as wings, because the organ served as a forearm (not a wing) in the last common ancestor of tetrapods. 

By definition, any homologous trait defines a clade–a monophyletic taxon in which all the members have the trait (or have lost it secondarily); and all non-members lack it.

Related terms

Cladistic terms 
Homoplasy: evolved independently, but from the same ancestral structure.
Plesiomorphy: present in a common ancestor but secondarily lost in some of its descendants.
Synapomorphy: present in an ancestor and all of its descendants.
Gene sequences 
Conserved sequences of DNA, RNA and proteins can be used to decide homologies between organisms.
Orthology: genes or sequences of DNA which are similar because they came from a common ancestor. They were originally separated by a speciation event. Orthologs (orthologous genes) are genes in different species which originated by vertical descent from a single gene of the last common ancestor. The term "ortholog" was coined in 1970 by Walter Fitch.

Paralogy: when a gene is duplicated to occupy two different places in the same genome, the two copies are paralogous. Paralogous genes often belong to the same species, but this is not necessary: for example, the haemoglobin gene of humans and the myoglobin gene of chimpanzees are paralogs. Paralogs typically have the same or similar function, but sometimes do not. At least one of the copies will be under less selection pressure, and may mutate and acquire a new function.
Xenology: Homologs resulting from horizontal gene transfer between two organisms. Xenologs can have different functions, if the new environment is vastly different for the horizontally moving gene. In general, though, xenologs typically have similar function in both organisms.

Deep homology 
In evolutionary developmental biology,  the concept of deep homology is used to describe cases where growth and differentiation are controlled by genetic mechanisms that are homologous and deeply conserved across a wide range of species. Textbook examples common to metazoa include the homeotic genes that control differentiation along the body, and pax genes (especially PAX6) involved in the development of the eye and other sensory organs.
An algorithm identifies deeply homologous genetic modules in unicellular organisms, plants, and non-human animals based on phenotypes (such as traits and developmental defects). The technique aligns phenotypes across organisms based on the homology of genes involved in the phenotypes.

References 

Biology
Discovery Channel (known as The Discovery Channel from 1985 to 1995, and often referred to as simply Discovery)  is an American cable channel owned by Warner Bros. Discovery, a publicly traded company run by CEO David Zaslav. As of June 2012, Discovery Channel was the third most widely distributed subscription channel in the United States, behind now-sibling channel EBS, BBC, ABC, CBS and PBS. it is available in 409 million households worldwide, through its U.S. flagship channel and its various owned or licensed television channels internationally.

It initially provided documentary television programming focused primarily on popular science, technology, and history, but by the 2010s had expanded into reality television and pseudo-scientific entertainment.

As of September 2018, Discovery Channel is available to approximately 88,589,000 pay television households in the United States.

References 

 
1985 establishments in the United States
The Last Day of the Dinosaurs is a 2010 Discovery Channel television documentary about the extinction of the dinosaurs. It portrays the asteroid as the cause of the extinction.

Featured genera
 Alamosaurus
 Ankylosaurus
 Charonosaurus
 Quetzalcoatlus
 Saurornithoides
 Triceratops
 Tyrannosaurus
 Mesodma
 Cockroach
 Scorpion

Plot
In the Pacific Northwest of North America, a Quetzalcoatlus is flying above the landscape, looking for food. It finds a nest of Tyrannosaurus babies that have just hatched. It picks them up in its beak and starts eating them. Suddenly, the father appears and starts fighting the Quetzalcoatlus. He grabs it by the wing, but it manages to escape. 

Meanwhile, the asteroid is getting closer to Earth. The narrator says that it was caused by the collision of two asteroids 150 million years ago. One of the fragments is heading towards Earth.
In the Pacific Northwest, two male Triceratops fight for mating rights. One of them wins. The loser walks away. Suddenly, two T. rexes attack and kill the Triceratops. They start feeding on its carcass.

In what is today central Mexico, a herd of Alamosaurus is roaming the plains in search of food. They are giants, even by dinosaur standards. They are 60 feet long and 40 feet tall, and they weigh 30 tons. Their huge size demands that they eat a lot of vegetation to maintain their bulk. Meanwhile, the asteroid enters the Earth's atmosphere. It is burning brighter than a million suns. The scorching light sears the ''Alamosaurus eyeballs, blinding them. 

Then the asteroid hits the Earth in the Gulf of Mexico, near the Yucatan Peninsula. In a fraction of a second, it disentegrates into the planet. The air temperature near the crash site now reaches 600 degrees Fahrenheit. The Alamosaurus are burned alive. In the Pacific Northwest, the Quetzalcoatlus can see the impact.
Meanwhile, Mongolia is 8,000 miles away from the point of impact. A herd of Charonosaurus is drinking at a watering hole. They are protecting their eggs. Suddenly, a Troodon appears. Its brain-to-body weight ratio is among the highest of any dinosaur. It steals an egg, but is seen by the mother. It runs into a cave. A second Saurornithoides is in the cave. The two predators start chasing the Charonosaurus. They jump on its neck and slash with their retractable toe claws, killing their prey. Then they start feasting on the carcass.
Millions of tons of dust and rock were thrown up into the air by the asteroid's impact. This is the ejecta cloud. In Mongolia, the ejecta cloud causes the temperature to become hotter. As the air temperature reaches 120 degrees, the Troodons run inside the cave. The temperature ticks upward every second. The Charonosaurus go into the cave. Inside the cave, it is cooler. However, the Charonosaurus and Troodon are forced to share the cave with each other, even though they are enemies.

Back in the Pacific Northwest, fires burn across the forest floor at 9 miles per hour. The Tyrannosaurus and the Triceratops are running to get away from the fire. The panicked animals race up the valley slopes.
In Mongolia, the temperatures are finally starting to decrease. The Troodon run outside and start feeding on a Charonosaurus corpse. Soon, the Charonosaurus follow. However, one stays near the protection of the cave. However, the dinosaurs are not safe yet. The ejecta cloud has caused a huge sandstorm. As it hits, the Troodons are small enough to crouch for cover. But the Charonosaurus are out in the open. The harder they struggle and the deeper they gasp for oxygen, the more sand fills their lungs, until finally, they can't breathe. It's hours before the winds die down. The last Charonosaurus, protected once again by the cave, finds that it's the last of the herd. But it's not the last remaining dinosaur in the neighborhood. The Troodons were sheltered from the worst of the storm. They have survived.
Instinct drives the Troodon back to their prime hunting spot, the watering hole, where the last remaining Charonosaurus is drinking. The Troodon are desperate for food. One of them has the confidence to attack. The Troodon runs to theCharonosaurus and leaps on it. It  starts slashing at its neck. The Charonosaurus is still too exhausted to run. Suddenly, the Charonosaurus crashes to the ground, crushing the Troodon to death under its weight. The remaining Troodon starts eating the dead body of its companion.
A week after impact, food is in very short supply across the entire planet. In the Pacific Northwest, two Triceratops are searching for food. Their hunger drives them to the Pacific coast. They see an island. Protected from the fires by the surrounding ocean, the island is lush and green. It has all the food that the Triceratops need. But when the asteroid hit the Earth, it caused an earthquake under the ocean. This causes a huge tsunami. The ocean is dragged back hundreds of feet. The path to the island is suddenly dry land. The Triceratops walk across the land bridge to the island. However, the tsunami crashes down on them, flooding the land. The Triceratops drown.
In the days and weeks that follow, few dinosaurs remain. In Mongolia, the starving Charonosaurus stays close to the cave that has saved it twice in the past. Suddenly, it collapses, but not from starvation. Bubbling to the surface from hot springs is one of nature's most toxic gases; Hydrogen Sulfide. The Troodon runs up to the dead Charonosaurus. Then it too dies from inhaling the poisonous gas.
In the Pacific Northwest, only a handful of dinosaurs patrol the gray wasteland. An Ankylosaurus, severely weakened by hunger, is searching for food. All it can find is a small bush. But even that won't come without a fight. A Triceratops roars at the Ankylosaurus. Suddenly, a T. rex appears. It roars at the herbivores. Then it kills the Triceratops. The Ankylosaurus tries to defend itself with its heavy tail club, but it's too weak to fight. The Tyrannosaurus flips the Ankylosaurus over and bites its soft underbelly, killing it. Then the Tyrannosaurus collapses from hunger. It falls on the Triceratops''' horn and is impaled by it after tripping over the Ankylosaurus.
In Mexico, the first region to be hit by the asteroid, life still remains. Buried in the cool ground inside its egg, an Alamosaurus baby has survived. And so has an adult Alamosaurus. All around the world, small handfuls of dinosaurs try to start over. But their species are already considered extinct. In order to survive, any species needs to maintain a critical mass of population. If it falls below that threshold, then there's no way to climb back from certain extinction.
But life on Earth is not completely destroyed. Out of the ruins, nature starts over. A group of animals that have long been limited in success by the dinosaurs now become the new rulers of the Earth: mammals. Eventually, they multiply and diversify. 10,000 species explode across the planet. And one species, humans, branches off from its relatives and comes down from the trees. They walk on two legs, evolve bigger brains, and eventually, they rule the planet. They build cities that touch the sky, vehicles that can leave the planet, and weapons that can destroy it.

In the end, the narrator says that humans would never have existed if a chance collision in space 150 million years ago had not occurred, sending an asteroid hurtling towards Earth and dooming the dinosaurs to extinction.
Inaccuracies
There is no evidence for a collision of meteorites. Meteorites tend to break up as they enter the atmosphere
 Troodon mongoliensis didn't live at the end of the age of dinosaurs. It lived in earlier stages of the Late Cretaceous.
 Charonosaurus wasn't discovered in Mongolia. It lived in northeastern China. It was found on the southern bank of the Amur River, on the border with Siberia.
Trivia
 The dinosaur models used here are the same as those used in Clash of the Dinosaurs. The Parasaurolophus was used for the Charonosaurus, the Deinonychus was used for Saurornithoides, and the Sauroposeidon model was used for Alamosaurus. The same Tyrannosaurus, Triceratops, Ankylosaurus, and Quetzalcoatlus models were also used.
 It is never shown how the female Quetzalcoatlus dies. However, she is last seen flying away from the tsunami, so it is presumed that she was killed by the tsunami.
 When the narrator explains that the air temperature is hot enough to boil away the water in the Alamosaurus skin, water is seen flying off the dinosaurs' necks.

References
http://dsc.discovery.com/videos/last-day-dinosaurs/

Dinosaurs
Television movies
2010s documentary movies
Discovery Channel
Charonosaurus was a genus of hadrosaur that lived at the very end of the Upper Cretaceous, about 65 million years ago. Its remains were found in China. 

The partial skull resembles that of Parasaurolophus from North America. This does not suggest a Bering land bridge existed during the Cretaceous period, since at that time North America was far away from Eastern Asia. Instead, it is likely that this group of hadrosaurs all had a similar long, backward-projecting hollow crest. It may have been used for trumpeting their calls. In other words, their skull shape was a basal feature.

Charonosaurus was a very large lambeosaurine hadrosaur (estimated around 13 m (42.5 ft) long), known from a partial skull found in Heilongjiang Province, northeastern China. Adult and juvenile hadrosaur remains were found in the same area. They give information on the rest of the skeleton; the femur length was up to 1.35 m. (4.5 ft).
In popular culture
Charonosaurus was featured in the Discovery Channel television documentary The Last Day of the Dinosaurs, where it was the prey of Troodon.

References 

Hadrosauridae
Cretaceous dinosaurs
Dinosaur brains and intelligence are interesting topics. Dinosaurs were once regarded as stupid animals, but it is now realised that some of the smaller carnivores had above average intelligence for reptiles. This idea led to exaggerated portrayals in films like Jurassic Park.

Stegosaurus 

The idea that Stegosaurus had a "brain the size of a walnut" (an oft-repeated phrase), was not quite accurate. It had a brain the size of a dog's, but in proportion to its body, the brain was very small. In the 1880s a well-preserved Stegosaurus braincase allowed Othniel Charles Marsh to get a cast of the brain cavity, which gave an idea of the brain size. The endocast showed that the brain was indeed small: relative to body size, maybe the smallest among the dinosaurs. The fact that an animal weighing over 4.5 metric tonnes (5 short tons) could have a brain of no more than 80 grams (2.8 oz) led to the idea that dinosaurs were unintelligent, an idea now largely rejected.
Marsh noted a large canal in the hip region of the spinal cord. It could have had 20 times the neurons of the famously small brain. This may have been used to coordinate the hind region in defence against theropod attack. This function for the "second brain" is not proved by any direct evidence.

Brain-body size relationship 
Brain size usually increases with body size in animals (is positively correlated). That means large animals usually have larger brains than smaller animals. The relationship is not linear however. Generally, small mammals have relatively larger brains than big ones. Mice have a direct brain/body size ratio similar to humans (1/40). Elephants have a comparatively small brain/body size (1/560), although elephants are obviously quite intelligent animals.
Encephalization quotient (EQ) 
The formula for the curve varies, but is usually given as Ew(brain) = 0.12w(body)2/3. As this formula is based on data from mammals, it should be applied to other animals with caution. For some of the other vertebrate classes the power of 3/4 rather than 2/3 is sometimes used, and for many groups of invertebrates the formula may give no meaningful results at all.
Intelligence 
Intelligence in animals is hard to establish, but the larger the brain is relative to the body, the more brain weight might be available for complex cognitive tasks. Rather than simply measuring raw brain weight, the EQ formula makes for a ranking of animals. The ranking coincides better with the observed complexity of behaviour. Mean EQ for mammals is around 1, with carnivora, cetacea and primates above 1, and insectivores and herbivores below. It also puts humans at the top of the list. The relationship between brain-to-body mass ratio and complexity of behaviour is not perfect, because other factors also influence intelligence. These factors include the evolution of the recent cerebral cortex and different degrees of brain folding. 

This increase the surface of the cortex is positively correlated to intelligence in humans.

Dinosaur brains
Dinosaur brains

Problems with EQ 
Traditional comparisons of brain volume to body mass in dinosaurs have estimated brain size as the volume of the endocast. However, the brain of the modern reptile genus Sphenodon fills only about half of its endocranial volume. Some paleontologists used this fifty percent estimate in their estimates of dinosaur brain volume. Other workers have observed that details on the endocranial surface indicates that some fossil reptiles had brains that occupied a much larger portion of the endocranium. Larsson notes that the transition from reptiles to birds prevents using a set ratio from being a valid approach to estimating the volume of the endocranium occupied by a dinosaur's brain.
Adding difficulty is the wide range of estimates for live mass. One study estimated that the live masses for many dinosaur genera had a four-fold range. Larsson laments that "the broad ranges of body mass estimates, combined with the ambiguous ratio of endocranial volume occupied by the brain, present a high degree of uncertainty for [creating an] index of brain size". Consequently, he attempted to minimize errors by making a different kind of comparison.

While it is difficult to estimate the absolute volume of the brain, the proportions of its various regions of the brain should be the same in the endocast as it was in the live brain. Larsson's study compared the ratio of the cerebrum, which is clearly marked on the inside of skulls, to the rest of the endocast's volume. According to Larsson, his technique is superior to traditional comparisons of brain volume to estimated live body mass.

Theropod brains
Theropod brains 

Most dinosaurs, and most theropods, had brains no better than present-day reptiles, so far as can be estimated. In a 2001 study of a Carcharodontosaurus saharicus endocast, Hans Larsson found that both C. saharicus and Allosaurus had a ratio of cerebrum to brain volume that was very similar to non-avian reptiles. By contrast, the Tyrannosaurus ratio was slightly in the direction of a more bird-like proportion. Since tyrannosaurs are relatively basal coelurosaurs, this is evidence that the Coelurosauria mark the beginning of a trend in theropod brain enlargement.

Troodon 
Troodon's cerebrum-to-brain-volume ratio was 31.5% to 63% of the way from a nonavian reptile proportion to a truly avian one.

Archaeopteryx 
Archaeopteryx had a cerebrum-to-brain-volume ratio 78% of the way to modern birds.
Summary 
The method used for Larsson's comparison was not the EQ, but a ratio of the size of the cerebrum to the whole brain. The cerebrum is chiefly responsible for what might be called 'intelligent behaviour'.

The brains of dinosaurs were generally much like other reptiles in their proportions. The exception is the coelurosaurs, which had cerebra proportionately larger than most reptiles, though proportionately smaller than modern birds.

References

Dinosaurs
Brain
Tellurium(IV) iodide, also known as tellurium tetraiodide, is a chemical compound. Its chemical formula is TeI4. It contains tellurium in its +4 oxidation state. It also contains iodide ions.

Properties
Tellurium(IV) iodide is a black solid. It breaks down when heated to tellurium(II) iodide and iodine. It is a weak reducing agent. It conducts electricity when melted.

Preparation
It is made by reacting tellurium with iodine or by reacting tellurium with iodomethane, CH3I.

Related pages
Tellurium(IV) bromide
Tellurium(IV) chloride
Tellurium(IV) fluoride

Tellurium compounds
Iodine compounds