parent_taxon delichon
A genus ( genera ) is a taxonomic rank used in the biological classification of living and fossil organisms in biology . In the hierarchy of biological classification , genus comes above species and below family . In binomial nomenclature , the genus name forms the first part of the binomial species name for each species within the genus . ___MASK2___ is a small genus of passerine birds that belongs to the swallow family and contains three species named as house martins . These are chunky , bull - headed and short - tailed birds , blackish - blue above with a contrasting white rump , and with white or grey underparts . They have feathering on the toes and tarsi that is characteristic of this genus . The house martins are closely related to other swallows that build mud nests , particularly the ___MASK7___ barn swallows . They breed only in Europe , Asia and the mountains of North Africa . Two species , the common and Asian house martins , migrate south in winter , while the Nepal house martin is resident in the Himalayas year - round . The house martins nest in colonies on cliffs or buildings , constructing feather - or grass - lined mud nests . The typical clutch is two or three white eggs ; both parents build the nest , incubate the eggs and feed the chicks . These martins are aerial hunters of small insects such as flies and aphids . Despite their flying skills the ___MASK2___ martins are sometimes caught by fast - flying birds of prey . They may carry fleas or internal parasites . None of the species are considered threatened , although widespread reductions in common house martin numbers have been reported from central and northern Europe . This decline is due to factors including poor weather , poisoning by agricultural pesticides , lack of mud for nest building and competition with house sparrows for nest sites . The Sahara (", ' the Greatest Desert ') is the largest hot desert and the third largest desert in the world after Antarctica and the Arctic . Its ___MASK56___ of is comparable to the ___MASK56___ of the United States . The Tibetan Plateau , also known in China as the Qinghai  Tibet Plateau or the Qingzang Plateau or Himalayan Plateau , is a vast elevated plateau in Central Asia and East Asia , covering most of the Tibet Autonomous Region and Qinghai Province in western China , as well as part of Ladakh in Jammu and Kashmir state of India . It stretches approximately north to south and east to west . With an average elevation exceeding , the Tibetan Plateau is sometimes called " the Roof of the World " and is the world ' s highest and largest plateau , with an ___MASK56___ of ( about five times the size of Metropolitan France ). Sometimes termed the Third Pole , the Tibetan Plateau contains the headwaters of the drainage basins of most of the streams in surrounding regions . Its tens of thousands of glaciers and other geographical and ecological features serve as a " water tower " storing water and maintaining flow . The impact of global warming on the Tibetan Plateau is of intense scientific interest . Africa is the world ' s second - largest and second - most - populous continent . At about 30 . 3 million km² ( 11 . 7 million square miles ) including adjacent islands , it covers 6 % of Earth ' s total surface ___MASK56___ and 20 . 4 % of its total land ___MASK56___ . With 1 . 1 billion people as of 2013 , it accounts for about 15 % of the world ' s human population . The continent is surrounded by the Mediterranean Sea to the north , both the Suez Canal and the Red Sea along the Sinai Peninsula to the northeast , the Indian Ocean to the southeast , and the Atlantic Ocean to the west . The continent includes Madagascar and various archipelagos . It contains 54 fully recognized sovereign states ( countries ), nine territories and two " de facto " independent states with limited or no recognition . Asia is Earth ' s largest and most populous continent , located primarily in the eastern and northern hemispheres and sharing the continental landmass of Eurasia with the continent of Europe . Asia covers an ___MASK56___ of , about 30 % of Earth ' s total land ___MASK56___ and 8 . 7 % of the Earth ' s total surface ___MASK56___ . The continent , which has long been home to the majority of the human population , was the site of many of the first civilizations . Asia is notable for not only its overall large size and population , but also dense and large settlements as well as vast barely populated regions within the continent of 4 . 4 billion people . Birds ( Aves ), also known as avian dinosaurs , are a group of endothermic vertebrates , characterised by feathers , toothless beaked jaws , the laying of hard - shelled eggs , a high metabolic rate , a four - chambered heart , and a lightweight but strong skeleton . Birds live worldwide and range in size from the bee hummingbird to the ___MASK94___ . They rank as the class of tetrapods with the most living species , at approximately ten thousand , with more than half of these being passerines , sometimes known as perching birds or , less accurately , as songbirds . Vertebrates comprise all species of animals within the subphylum ___MASK37___ ( chordates with backbones ). Vertebrates represent the overwhelming majority of the phylum Chordata , with currently about 64 , 000 species described . Vertebrates include the jawless fish and the jawed vertebrates , which include the cartilaginous fish ( sharks and rays ) and the bony fish . A songbird is a ___MASK27___ belonging to the clade ___MASK8___ of the perching birds ( Passeriformes ). Another name that is sometimes seen as a scientific or vernacular name is Oscines , from Latin " oscen ", " a songbird ". This group contains some 4 , 000 species found all over the world , in which the vocal organ typically is developed in such a way as to produce a diverse and elaborate ___MASK27___ song . Egypt (; ', , " Kimi "), officially the Arab Republic of Egypt , is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia by a land bridge formed by the Sinai Peninsula . Egypt is a Mediterranean country bordered by the ___MASK55___ Strip and Israel to the northeast , the Gulf of Aqaba to the east , the Red Sea to the east and south , Sudan to the south , and Libya to the west . Across the Gulf of Aqaba lies Jordan , and across from the Sinai Peninsula lies Saudi Arabia , although Jordan and Saudi Arabia do not share a land border with Egypt . It is the world ' s only contiguous Afrasian nation . The Himalayas , or Himalaya , ( or ) are a mountain range in Asia separating the plains of the Indian subcontinent from the Tibetan Plateau . Cowbirds are birds belonging to the genus Molothrus in the family ___MASK87___ . They are brood parasitic New World birds which are unrelated to the Old World cuckoos , one of which , the common cuckoo , is the most famous brood parasitic ___MASK27___ . Mammals are any vertebrates within the class Mammalia ( from Latin " mamma " " breast "), a clade of endothermic amniotes distinguished from reptiles and birds by the possession of a neocortex ( a region of the brain ), hair , three middle ear bones and mammary glands . The sister group of mammals may be the extinct " Haldanodon ." The mammals represent the only living Synapsida , which together with the ___MASK69___ form the Amniota clade . The mammals consist of the Yinotheria including monotrema and the Theriiformes including the ___MASK29___ . A mountain range ( also mountain barrier , belt , or system ) is a geographic ___MASK56___ containing numerous geologically related mountains . A mountain system or system of mountain ranges , sometimes is used to combine several geological features that are geographically ( regionally ) related . On Earth , most significant mountain ranges are the result of plate tectonics , though mountain ranges are formed by a range of processes , are found on many planetary mass objects in the Solar System and are likely a feature of most terrestrial planets . China , officially the People ' s Republic of China ( PRC ), is a unitary sovereign state in East Asia . With a population of over 1 . 381 billion , it is the world ' s most populous country . The state is governed by the Communist Party of China , and its capital is Beijing . It exercises jurisdiction over 22 provinces , five autonomous regions , four direct - controlled municipalities ( Beijing , Tianjin , Shanghai , and Chongqing ), and two mostly self - governing special administrative regions ( Hong Kong and Macau ), and claims sovereignty over Taiwan . The country ' s major urban ___MASK77___ include Shanghai , Guangzhou , Beijing , Chongqing , Shenzhen , Tianjin and Hong Kong . China is a great power and a major regional power within Asia , and has been characterized as a potential superpower . North Africa or Northern Africa is the northernmost region of Africa . The United Nations definition of " North Africa " includes seven countries and territories ; Algeria , Egypt , Libya , Mauritania , Morocco , Sudan , Tunisia , and Western Sahara . The countries of Algeria , Morocco , Tunisia , and Libya are often collectively referred to as the Maghreb , which is the Arabic word for " sunset ". Egypt lies to the northeast and encompasses part of West Asia , while Sudan is situated on the edge of the Sahel , to the south of Egypt . Brood parasites are organisms that rely on others to raise their young . The strategy appears among birds , ___MASK70___ and some fish . The brood parasite manipulates a host , either of the same or of another species , to raise its young as if it were its own . In biology , a species ( abbreviated sp ., with the plural form species abbreviated spp .) is the basic unit of biological classification and a taxonomic rank . A species is often defined as the largest group of organisms in which two individuals can produce fertile offspring , typically by sexual reproduction . While this definition is often adequate , looked at more closely it is often problematic . For example , in a species complex , the boundaries between closely related species become unclear or disappear altogether . Other ways of defining species include similarity of DNA , morphology , or ecological niche . The presence of locally adaptive traits may further subdivide species into infraspecific taxa such as subspecies . The Maghreb ( or ; literally " sunset "; ', " the Arab West " previously known as Barbary Coast , derived from Berber ), or the Greater Maghreb (" al - Maghrib al - Kabr "), is usually defined as much or most of the region of western North Africa or Northwest Africa , west of Egypt . The traditional definition as the region including the Atlas Mountains and the coastal plains of Morocco , Algeria , Tunisia , and Libya , was later superseded , especially following the 1989 formation of the Arab Maghreb Union (    ), by the inclusion of Mauritania and of the disputed territory of Western Sahara ( mostly controlled by Morocco ). During the Al - Andalus era in Spain ( 711  1492 ), the Maghreb ' s inhabitants , Maghrebis , were known as " Moors "; the Muslim ___MASK77___ of Spain in those times were usually included in contemporary definitions of the Maghreb  hence the use of " Moorish " or " Moors " to describe the Muslim inhabitants of Spain in Western sources . Algeria (' " Dzayer "), officially the People ' s Democratic Republic of Algeria , is a sovereign state in North Africa on the Mediterranean coast . Its capital and most populous city is Algiers , located in the country ' s far north . With an ___MASK56___ of , Algeria is the tenth - largest country in the world , and the largest in Africa . Algeria is bordered to the northeast by Tunisia , to the east by Libya , to the west by Morocco , to the southwest by the Western Saharan territory , Mauritania , and Mali , to the southeast by Niger , and to the north by the Mediterranean Sea . The country is a semi - presidential republic consisting of 48 provinces and 1 , 541 communes ( counties ). Abdelaziz Bouteflika has been President since 1999 . Deoxyribonucleic acid ( DNA ) is a molecule that carries the genetic instructions used in the growth , development , functioning and reproduction of all known living organisms and many viruses . DNA and RNA are nucleic acids ; alongside proteins , lipids and complex carbohydrates ( polysaccharides ), they are one of the four major types of macromolecules that are essential for all known forms of life . Most DNA molecules consist of two biopolymer strands coiled around each other to form a double ___MASK10___ . The cuckoos are a family of birds , ___MASK96___ , the sole taxon in the order Cuculiformes . The cuckoo family includes the common or European cuckoo , roadrunners , koels , malkohas , couas , coucals and anis . The coucals and anis are sometimes separated as distinct families , the Centropodidae and Crotophagidae respectively . The order ___MASK43___ , or the scaled reptiles , are the largest recent order of reptiles , comprising all lizards and snakes . With over 10 , 000 species , it is also the second - largest order of extant vertebrates , after the perciform fish , and roughly equal in number to the Saurischia ( one of the 2 major groups of dinosaurs ). Members of the order are distinguished by their skins , which ___MASK66___ horny scales or shields . They also possess movable quadrate bones , making it possible to move the upper jaw relative to the neurocranium . This is particularly visible in snakes , which are able to open their mouths very wide to accommodate comparatively large prey . They are the most variably sized order of reptiles , ranging from the dwarf gecko (" Sphaerodactylus ariasae ") to the green anaconda (" Eunectes murinus ") and the now - extinct mosasaurs , which reached lengths of . The barn swallow (" ___MASK7___ rustica ") is the most widespread species of swallow in the world . It is a distinctive passerine bird with blue upperparts , a long , deeply forked tail and curved , pointed wings . It is found in Europe , Asia , Africa and the Americas . In Anglophone Europe it is just called the swallow ; in Northern Europe it is the only common species called a " swallow " rather than a " martin ". The United Nations ( UN ) is an intergovernmental organization to promote international co - operation . A replacement for the ineffective League of Nations , the organization was established on 24 October 1945 after World War II in order to prevent another such conflict . At its founding , the UN had 51 member states ; there are now 193 . The headquarters of the United Nations is in Manhattan , New York City , and experiences extraterritoriality . Further main offices are situated in Geneva , Nairobi , and Vienna . The organization is financed by assessed and voluntary contributions from its member states . Its objectives include maintaining international peace and security , promoting ___MASK58___ rights , fostering social and economic development , protecting the environment , and providing humanitarian aid in cases of famine , natural disaster , and armed conflict . Sexual reproduction is a form of reproduction where two morphologically distinct types of specialized reproductive cells called gametes fuse together , involving a female ' s large ovum ( or egg ) and a male ' s smaller sperm . Each gamete contains half the number of chromosomes of normal cells . They are created by a specialized type of cell division , which only occurs in eukaryotic cells , known as meiosis . The two gametes fuse during fertilization to produce DNA replication and the creation of a single - celled zygote which includes genetic material from both gametes . In a process called genetic recombination , genetic material ( DNA ) joins up so that homologous chromosome sequences are aligned with each other , and this is followed by exchange of genetic information . Two rounds of cell division then produce four daughter cells with half the number of chromosomes from each original parent cell , and the same number of chromosomes as both parents , though self - fertilization can occur . For instance , in ___MASK58___ reproduction each ___MASK58___ cell contains 46 chromosomes , 23 pairs , except gamete cells , which only contain 23 chromosomes , so the child will have 23 chromosomes from each parent genetically recombined into 23 pairs . Cell division initiates the development of a new individual organism in multicellular organisms , including animals and plants , for the vast majority of whom this is the primary method of reproduction . Libya ("") is a country in the Maghreb region of North Africa , bordered by the Mediterranean Sea to the north , Egypt to the east , Sudan to the southeast , Chad and Niger to the south , and Algeria and Tunisia to the west . The three traditional parts of the country are Tripolitania , Fezzan and Cyrenaica . With an ___MASK56___ of almost , Libya is the fourth largest country in Africa , and is the 16th largest country in the world . Libya has the 10th - largest proven oil reserves of any country in the world . Rodents ( from Latin " rodere ", " to gnaw ") are mammals of the order ___MASK48___ , which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws . About 40 % of all mammal species are rodents ; they are found in vast numbers on all continents except Antarctica . They are the most diversified mammalian order and live in a variety of terrestrial habitats , including human - made environments . In biology , an organism is any contiguous living system , such as an ___MASK11___ , ___MASK67___ , fungus , archaeon , or bacterium . All known types of organisms are capable of some degree of response to stimuli , reproduction , growth and development and homeostasis . An organism consists of one or more cells ; when it has one cell it is known as a unicellular organism ; and when it has more than one it is known as a multicellular organism . Most unicellular organisms are of microscopic scale and are thus loosely described as microorganisms . Humans are multicellular organisms composed of many trillions of cells grouped into specialized tissues and organs . Western Sahara ("") is a disputed territory in the Maghreb region of North Africa , bordered by Morocco to the north , Algeria to the northeast , Mauritania to the east and south , and the Atlantic Ocean to the west . Its surface ___MASK56___ amounts to . It is one of the most sparsely populated territories in the world , mainly consisting of desert flatlands . The population is estimated at just over 500 , 000 , of which nearly 40 % live in Laayoune , the largest city in Western Sahara . The cuckoo - finch (" ___MASK88___ imberbis "), also known as the parasitic weaver or cuckoo weaver , is a small passerine ___MASK27___ now placed in the family Viduidae with the indigobirds and whydahs . It occurs in grassland in Africa south of the Sahara . The male is mainly yellow and green while the female is buff with dark streaks . The eggs are laid in the nests of other birds . Nepal , officially the Federal Democratic Republic of Nepal , is a landlocked central Himalayan country in South Asia . It has a population of 26 . 4 million and is the 93rd largest country by ___MASK56___ . Bordering China in the north and India in the south , east , and west , it is the largest sovereign Himalayan state . Nepal does not border Bangladesh , which is located within only 27 km ( 17 mi ) of its southeastern tip . It neither borders Bhutan due to the Indian state of Sikkim being located in between . Nepal has a diverse geography , including fertile plains , subalpine forested hills , and eight of the world ' s ten tallest mountains , including Mount Everest , the highest point on Earth . Kathmandu is the nation ' s capital and largest city . It is a multiethnic nation with Nepali as the official language . Shrikes are carnivorous passerine birds of the family Laniidae . The family is composed of thirty - one species in four genera . They are fairly closely related to the bush - ___MASK65___ family Malaconotidae . The ___MASK27___ genus ___MASK7___ is a group of passerines in the family ___MASK31___ ( swallows and martins ). The genus name is the Latin for a swallow . These are the typical swallows , including the widespread barn swallow . Many of this group have blue backs , red on the face and sometimes the rump or nape , and whitish or rufous underparts . With fourteen species this genus is the largest in its family . The swallows and martins are a group of passerine birds in the family ___MASK31___ that are characterised by their adaptation to aerial feeding . " Swallow " is used colloquially in Europe as a synonym for the barn swallow . Tibet ( Tibetan Pinyin : " boe ", ; / i t  s¹ /) is a region on the Tibetan Plateau in Asia . It is the traditional homeland of the Tibetan people as well as some other ethnic groups such as Monpa , Qiang , and Lhoba peoples and is now also inhabited by considerable numbers of ___MASK59___ Chinese and Hui people . Tibet is the highest region on Earth , with an average elevation of . The highest elevation in Tibet is Mount Everest , Earth ' s highest mountain , rising 8 , 848 m ( 29 , 029 ft ) above sea level . A passerine is any ___MASK27___ of the order Passeriformes , which includes more than half of all ___MASK27___ species . A notable feature of passerines compared to other orders of Aves is the arrangement of their toes , three pointing forward and one back , which facilitates perching . Sometimes known as perching birds or , less accurately , as songbirds , the passerines form one of the most diverse terrestrial vertebrate orders , with over 5 , 000 identified species . It has roughly twice as many species as the largest of the ___MASK83___ orders , the ___MASK48___ . It contains more than 110 families , the second - most of any order of tetrapods ( after Squamata , the scaled reptiles ). The passerines contain several groups of brood parasites such as the viduas , cuckoo - finches , and the cowbirds . Most passerines are omnivorous , while the shrikes are carnivorous . The Nepal house martin (" ___MASK2___ nipalense ") is a non - migratory passerine of the swallow family ___MASK31___ . Its two subspecies breed in the Himalayas from northwestern India through Nepal to Burma , northern Vietnam , and just into China . It occurs in river valleys and rugged wooded mountain ridges at heights between altitude , where it nests in colonies beneath overhangs on vertical cliffs , laying three or four white eggs in an enclosed mud nest . Tunisia ('; ), officially the Republic of Tunisia (') is the northernmost country in Africa , covering . Its northernmost point , Cape ___MASK79___ , is the northernmost point on the African continent . It is bordered by Algeria to the west and southwest , Libya to the southeast , and the Mediterranean Sea to the north and east . Tunisia ' s population was estimated to be just under 11 million in 2014 . Tunisia ' s name is derived from its capital city , Tunis , which is located on Tunisia ' s northeast coast . India , officially the Republic of India (" Bhrat Gaarjya "), is a country in South Asia . It is the seventh - largest country by ___MASK56___ , the second - most populous country ( with over 1 . 2 billion people ), and the most populous democracy in the world . It is 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 northeast ; and Myanmar ( Burma ) and Bangladesh to the east . In the Indian Ocean , India is in the vicinity of Sri Lanka and the Maldives . India ' s Andaman and Nicobar Islands share a maritime border with Thailand and Indonesia . Its capital is New Delhi ; other metropolises include Mumbai , Kolkata , Chennai , Bangalore , Hyderabad and Ahmedabad . Binomial nomenclature ( also called binominal nomenclature or binary nomenclature ) is a formal system of naming species of living things by giving each a name composed of two parts , both of which use Latin grammatical forms , although they can be based on words from other languages . Such a name is called a binomial name ( which may be shortened to just " binomial "), a binomen or a scientific name ; more informally it is also called a Latin name . The first part of the name identifies the genus to which the species belongs ; the second part identifies the species within the genus . For example , humans belong to the genus " ___MASK12___ " and within this genus to the species " ___MASK12___ sapiens ". The " formal " introduction of this system of naming species is credited to Carl Linnaeus , effectively beginning with his work " Species Plantarum " in 1753 . But Gaspard Bauhin , in as early as 1623 , had introduced in his book " Pinax theatri botanici " ( English , " Illustrated exposition of plants ") many names of genera that were later adopted by Linnaeus . ___MASK60___ is a genus of sparrows , also known as the true sparrows . The genus includes the house sparrow and the Eurasian tree sparrow , some of the most common birds in the world . They are small birds with thick bills for eating seeds , and are mostly coloured grey or brown . Native to the Old World , some species have been introduced throughout the world .