Question: Information: - Protist is an informal term for any eukaryotic organism that is not an animal, plant or fungus. The protists do not form a natural group, or clade, but are often grouped together for convenience, like algae or invertebrates. In some systems of biological classification, such as the popular 5-kingdom scheme proposed by Robert Whittaker in 1969, the protists make up a kingdom called Protista, composed of "organisms which are unicellular or unicellular-colonial and which form no tissues." - The metamonads are a large group of flagellate amitochondriate protozoa . Their composition is not entirely settled , but they include the retortamonads , diplomonads , and possibly the parabasalids and oxymonads as well . These four groups are all anaerobic , occurring mostly as symbiotes of animals . - A flagellate is a cell or organism with one or more whip-like organelles called flagella. The word "flagellate" also describes a particular construction (or level of organization) characteristic of many protists (eukaryotic organisms) and their means of motion. The term presently does not imply any specific relationship or classification of the organisms that possess flagellae. However, the term "flagellate" is included in other terms (such as "dinoflagellate" and "choanoflagellata") which are more formally characterized. - The retortamonads are a small group of flagellates, most commonly found in the intestines of animals as commensals, although a free-living species called the "Chilomastix cuspidata" exists. They are grouped under the taxon, Archezoa. They are usually around 5-20 m in length, and all of their small subunit ribosomal RNA gene sequences are very similar to each other. There are two genera: "Retortamonas" with two flagella, and "Chilomastix" with four. In both cases there are four basal bodies anterior to a prominent feeding groove, and one flagellum is directed back through the cell, emerging from the groove. - The dinoflagellates (Greek "dinos" "whirling" and Latin "flagellum" "whip, scourge") are a large group of flagellate protists that constitute the phylum Dinoflagellata. Most are marine plankton, but they are common in freshwater habitats, as well. Their populations are distributed depending on temperature, salinity, or depth. Many dinoflagellates are known to be photosynthetic, but a large fraction of these are in fact mixotrophic, combining photosynthesis with ingestion of prey (phagotrophy). In terms of number of species, dinoflagellates form one of the largest groups of marine eukaryotes, although this group is substantially smaller than the diatoms. Some species are endosymbionts of marine animals and play an important part in the biology of coral reefs. Other dinoflagellates are unpigmented predators on other protozoa, and a few forms are parasitic (see for example "Oodinium", "Pfiesteria"). Some dinoflagellates produce resting stages, called dinoflagellate cysts or dinocysts, as part of their lifecycles. What entity does 'metamonad' has the relation 'instance of' with?
Answer: taxon

input: Please answer the following: Information: - Chicago Transit Authority, also known as CTA, is the operator of mass transit in Chicago, Illinois and some of its surrounding suburbs, including the trains of the Chicago "L" and CTA bus service. - The Chicago Surface Lines (CSL) was operator of the street railway system of Chicago, Illinois, from the years 1913 to 1947. The firm is a predecessor of today's publicly owned operator, the Chicago Transit Authority. - North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere. It can also be considered a northern subcontinent of the Americas. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the southeast by South America and the Caribbean Sea. - The Chicago metropolitan area, or Chicagoland, is the metropolitan area associated with the city of Chicago, Illinois, and its suburbs. With an estimated population of 9.4 million people, it is the third largest metropolitan area in the United States. Chicagoland is the area that is closely linked to the city through geographic, social, economic, and cultural ties. - A county is a geographical region of a country used for administrative or other purposes, in certain modern nations. The term is derived from the Old French "conte" or "cunte" denoting a jurisdiction under the sovereignty of a count (earl) or a viscount. The modern French is "comte", and its equivalents in other languages are "contea", "contado", "comtat", "condado", "Grafschaft", "graafschap", "Gau", etc. (cf. "conte", "comte", "conde", "Graf"). - The Midwestern United States, also referred to as the American Midwest or simply the Midwest, is one of the four geographic regions defined by the United States Census Bureau, occupying the northern central part of the United States of America. It was officially named the North Central region by the Census Bureau until 1984. - Chicago (or ), officially the City of Chicago, is the third-most populous city in the United States, and the fifth-most populous city in North America. With over 2.7million residents, it is the most populous city in the state of Illinois and the Midwestern United States, and the county seat of Cook County. The Chicago metropolitan area, often referred to as Chicagoland, has nearly 10million people and is the third-largest in the U.S. - Illinois is a state in the midwestern region of the United States, achieving statehood in 1818. It is the 5th most populous state and 25th largest state in terms of land area, and is often noted as a microcosm of the entire country. The word "Illinois" comes from the Algonquin word for "tribe of superior men". With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal, timber, and petroleum in the south, Illinois has a diverse economic base and is a major transportation hub. The Port of Chicago connects the state to other global ports from the Great Lakes, via the Saint Lawrence Seaway, to the Atlantic Ocean, as well as the Great Lakes to the Mississippi River, via the Illinois River. For decades, O'Hare International Airport has been ranked as one of the world's busiest airports. Illinois has long had a reputation as a bellwether both in social and cultural terms and politics. - The Chicago City Railway Company ( CCRy ) was an urban transit company that operated horse , cable , and electric streetcars on Chicago 's South Side between 1859 and 1914 , when it became merged into and part of the Chicago Surface Lines ( CSL ) metropolitan - wide system . After that time it owned electric streetcars , along with gasoline , diesel , and propane - fueled transit busses . Purchased by the government agency Chicago Transit Authority ( CTA ) in 1947 , it was liquidated in 1950 . What entity does 'chicago city railway' has the relation 'instance of' with?
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output:
railway system