chondrite: These are carbonaceous chondrites, ordinary chondrites, and enstatite chondrites.

poison: Allergies: …caused by the terms hypersensitivity, hypersusceptibility, and idiosyncrasy. Hypersensitivity is a reaction to a chemical or substance in certain individuals and has a basis in the immune system. Hypersusceptibility is an increased predisposition of certain individuals to react to a chemical. Because of biological variability among humans, some individuals respond…

Hypertalk, a computer programming language designed in 1985 as “programming for the rest of us” by American computer scientist Bill Atkinson for Apple’s Macintosh. Using a simple English-like syntax, Hypertalk enabled anyone to combine text, graphics, and audio quickly into “linked stacks” that

pharmaceutical industry: Contribution of scientific knowledge to drug discovery: …inactive angiotensin I to active angiotensin II by angiotensin-converting enzyme (ACE) and the interaction of angiotensin II with its physiologic receptors, including AT1 receptors. Angiotensin II interacts with AT1 receptors to raise blood pressure. Knowledge of the biochemistry and physiology of this system suggested to scientists that new drugs could…

hypertension, condition that arises when the blood pressure is abnormally high. Hypertension occurs when the body’s smaller blood vessels (the arterioles) narrow, causing the blood to exert excessive pressure against the vessel walls and forcing the heart to work harder to maintain the pressure.

HTML, a formatting system for displaying material retrieved over the Internet. Each retrieval unit is known as a Web page (from World Wide Web), and such pages frequently contain hypertext links that allow related pages to be retrieved. HTML is the markup language for encoding Web pages. It was

HTTP, standard application-level protocol used for exchanging files on the World Wide Web. HTTP runs on top of the TCP/IP protocol and (later) on the QUIC protocol. Web browsers are HTTP clients that send file requests to Web servers, which in turn handle the requests via an HTTP service. HTTP was

digital certificate: …as the security basis for HTTPS (Hypertext Transfer Protocol Secure).

hyperthelia, abnormal presence of accessory nipples, a condition of relatively frequent occurrence (1 percent of male and female human population). The nipples usually occur along the primitive milk line, between the armpit and groin, corresponding to the distribution in lower animals. Usually

therapeutics: Hyperthermia: Some tumours are more sensitive than the surrounding healthy tissue to temperatures around 43 °C (109.4 °F). Sensitivity to heat is increased in the centre of tumours, where the blood supply is poor and radiation is less effective. A tumour may be heated using…

extremophile: …°C [140 and 176 °F]); hyperthermophilic (optimal growth above 80 °C [176 °F]); psychrophilic (optimal growth at 15 °C [60 °F] or lower, with a maximum tolerant temperature of 20 °C [68 °F] and minimal growth at or below 0 °C [32 °F]); piezophilic, or barophilic (optimal growth at high…

extremophile: …°C [140 and 176 °F]); hyperthermophilic (optimal growth above 80 °C [176 °F]); psychrophilic (optimal growth at 15 °C [60 °F] or lower, with a maximum tolerant temperature of 20 °C [68 °F] and minimal growth at or below 0 °C [32 °F]); piezophilic, or barophilic (optimal growth at high…

hyperthyroidism, excess production of thyroid hormone by the thyroid gland. Most patients with hyperthyroidism have an enlarged thyroid gland (goitre), but the characteristics of the enlargement vary. Examples of thyroid disorders that give rise to hyperthyroidism include diffuse goitre (Graves

time: Time in the special theory of relativity: …advance with respect to a hypertime, perhaps a new time direction orthogonal to the old one. Perhaps it could be a fifth dimension, as has been used in describing the de Sitter universe as a four-dimensional hypersurface in a five-dimensional space. The question may be asked, however, what advantage such…

artiodactyl: Evolution and paleontology: The hypertragulids were a mainly Oligocene group of chevrotain-like forms related to the Protoceratidae. The latter had horns above their noses, a position unique among artiodactyls, as well as in the usual position. The North American Miocene (23 million to 5.3 million years ago) produced some…

artiodactyl: Evolution and paleontology: The hypertragulids were a mainly Oligocene group of chevrotain-like forms related to the Protoceratidae. The latter had horns above their noses, a position unique among artiodactyls, as well as in the usual position. The North American Miocene (23 million to 5.3 million years ago) produced some…

hypertrichosis, excessive abnormal hairiness that may be localized or cover the entire body. Hypertrichosis is associated with disorders such as anorexia, repeated skin trauma, systemic illness, metabolic disease, and exposure to certain drugs and chemicals. In very rare instances the disorder is

cardiomyopathy: In hypertrophic cardiomyopathy, the ventricles are quite small owing to abnormal growth and arrangement of the cardiac muscle fibres. This form of the disease is often hereditary and has been associated with mutations in several different genes, each of which encodes a protein necessary for the…

joint disease: Hypertrophic osteoarthropathy: In approximately 5 to 10 percent of persons who have primary tumours within the chest, the ends of the bones near the joints become enlarged and painful. New bone is formed in the periosteum, and only occasionally do abnormalities develop within the joints…

scar: …of overscarring is that of hypertrophic scars, in which the scar grows overly thick but remains confined within the limits of the wound. Keloids and hypertrophic scars are most troublesome when they result from serious burns and cover large areas of the skin; these may inhibit a person’s movement, especially…

spondylitis: Hypertrophic spondylitis, also known as osteoarthritis of the spine, is a degenerative disease seen mostly in individuals over the age of 50. It is characterized by the destruction of intervertebral disks and the growth of spurs on the vertebrae themselves. Treatment includes rest, the application…

human disease: Health versus disease: …(the process is known as hypertrophy). This occurs in certain forms of heart disease, especially in those involving long-standing high blood pressure or structural defects of the heart valves. A large heart, therefore, may be a sign of disease. On the other hand, it is not uncommon for athletes to…

arthritis: Crystalloid arthritis: …uric acid excretion, leading to hyperuricemia. Although acute gouty attacks are self-limited when hyperuricemia is left untreated for years, such attacks can recur intermittently, involving multiple joints. Chronic tophaceous gout occurs when, after about 10 years, chalky, pasty deposits of monosodium urate crystals begin to accumulate in the soft tissue,…

chemical bonding: Hypervalence: Lewis structures and the octet rule jointly offer a succinct indication of the type of bonding that occurs in molecules and show the pattern of single and multiple bonds between the atoms. There are many compounds, however, that do not conform to the octet…

chemical bonding: Hypervalence: Lewis structures and the octet rule jointly offer a succinct indication of the type of bonding that occurs in molecules and show the pattern of single and multiple bonds between the atoms. There are many compounds, however, that do not conform to the octet…

maple syrup urine disease: …acids are isovaleric acidemia and hypervalinemia. In the former, the metabolism of leucine alone is blocked at one specific step by a defect in an enzyme called isovaleryl coenzyme A dehydrogenase. As a result, the level of isovaleric acid rises markedly in body fluids, and the affected individual suffers from…

meteorite crater: The impact-cratering process: …extreme speeds is called a hypervelocity impact. Although the resulting depression may bear some resemblance to the hole that results from throwing a pebble into a sandbox, the physical process that occurs is actually much closer to that of an atomic bomb explosion. A large meteorite impact releases an enormous…

hyperventilation, sustained abnormal increase in breathing. During hyperventilation the rate of removal of carbon dioxide from the blood is increased. As the partial pressure of carbon dioxide in the blood decreases, respiratory alkalosis, characterized by decreased acidity or increased alkalinity

nutritional disease: Vitamins: Chronic hypervitaminosis A, usually resulting from a sustained daily intake of 30,000 μg (100,000 IU) for months or years, may result in wide-ranging effects, including loss of bone density and liver damage. Vitamin A toxicity in young infants may be seen in a swelling of the…

vitamin D: …toxic levels, a condition called hypervitaminosis D. An individual experiencing vitamin D poisoning may complain of weakness, fatigue, loss of appetite, nausea, and vomiting. In infants and children there may be growth failure. Because vitamin D is involved in the intestinal absorption and mobilization of calcium, this mineral may reach…

Basidiomycota: …typically filamentous fungi composed of hyphae. Most species reproduce sexually with a club-shaped spore-bearing organ (basidium) that usually produces four sexual spores (basidiospores). Basidia are borne on fruiting bodies (basidiocarps), which are large and conspicuous in all but the yeasts, rusts, and smuts.

Basidiomycota: …typically filamentous fungi composed of hyphae. Most species reproduce sexually with a club-shaped spore-bearing organ (basidium) that usually produces four sexual spores (basidiospores). Basidia are borne on fruiting bodies (basidiocarps), which are large and conspicuous in all but the yeasts, rusts, and smuts.

palm: Distribution: (palmyra palm), Calamus (rattan palm), Hyphaene (doum palm), and Phoenix (date palm) in Africa and Asia. Numbers of individuals of a species may be few or many.

palm: Distribution: …and coastal plains of Africa, Hyphaene compressa and Borassus aethiopum occur, often in great abundance. Freshwater swamplands in parts of New Guinea are dominated by Metroxylon sagu. Both the doum palm and the sago palm (Metroxylon) are useful, and their distribution may be due in part to human activities. Eugeissona…

fungus: Predation: Other fungi produce hyphal loops that ensnare small animals, thereby allowing the fungus to use its haustoria to penetrate and kill a trapped animal. Perhaps the most amazing of these fungal traps are the so-called constricting rings of some species of Arthrobotrys, Dactylella, and Dactylaria—soil-inhabiting fungi easily grown…

Beas River, river in Himachal Pradesh and Punjab states, northwestern India. It is one of the five rivers that give the Punjab (“Five Rivers”) its name. The Beas rises at an elevation of 14,308 feet (4,361 metres) at Rohtang Pass in the western (Punjab) Himalayas (a section of the vast Himalayas

hyphen, punctuation mark (-) used to connect word elements that are written disjointedly or to divide a word at the end of a line of text. The hyphen’s lineage is traced to a punctuation mark created by Dionysius Thrax, a Classical Greek grammarian who flourished in the late Hellenistic period when

tetra: The neon tetra (Paracheirodon, or Hyphessobrycon, innesi) is a slender fish that is very popular with aquarium owners. It grows to a length of 4 cm, its hind parts are coloured a gleaming red, and its sides have a neonlike blue-green stripe. The cardinal tetra (Cheirodon…

borane: Structure and bonding of boranes: …with two missing vertices; (4) hypho- (Greek, meaning “to weave” or “a net”), the most open clusters, with boron atoms occupying n corners of an (n + 3)-cornered closo-polyhedron; and (5) klado- (Greek, meaning “branch”), n vertices of an n + 4-vertex closo-polyhedron occupied by n boron atoms. Members of…

carborane: Reactions and synthesis of carboranes: The first hypho-carborane, C3B4H12, was reported in 1993 by Robert Greatrex, Norman N. Greenwood, and their colleagues.

fungus: Annotated classification: Order Hyphochytriales Mostly marine; motile cells bear a single tinsel flagellum (a flagellum with short side branches along the central axis, comblike); example genera include Hyphochytrium and Rhizidiomyces. Phylum Labyrinthulomycota Found in both salt water and fresh water in association with algae and other chromists; feeding…

Hyphochytriomycota, phylum of mostly aquatic funguslike organisms in the kingdom Chromista. The taxonomy of the group is contentious but is generally thought to contain about 20 species. The phylum is distinguished by the asexual production of motile cells (zoospores) with a single, anterior,

bacteria: Budding: In Hyphomicrobium a hyphal filament (prostheca) grows out of one end of the cell, and the bud grows out of the tip of the prostheca, separated by a relatively long distance from the mother cell.

dream: Dreamlike activities: …as he awakens, respectively called hypnagogic and hypnopompic reveries. During sleep itself there are nightmares, observable signs of sexual activity, and sleepwalking. Even people who ostensibly are awake may show evidence of such related phenomena as hallucinating, trance behaviour, and reactions to drugs.

graphic design: Renaissance book design: …was the Aldine Press’s 1499 Hypnerotomachia Poliphili, believed to be written by Francesco Colonna. The design of the work achieves an understated simplicity and tonal harmony, and its elegant synthesis of type and image has seldom been equaled. The layout combined exquisitely light woodcuts by an anonymous illustrator with roman…

dream: Dreamlike activities: respectively called hypnagogic and hypnopompic reveries. During sleep itself there are nightmares, observable signs of sexual activity, and sleepwalking. Even people who ostensibly are awake may show evidence of such related phenomena as hallucinating, trance behaviour, and reactions to drugs.

Hypnos, Greco-Roman god of sleep. Hypnos was the son of Nyx (Night) and the twin brother of Thanatos (Death). In Greek myth he is variously described as living in the underworld or on the island of Lemnos ( according to Homer) or (according to Book XI of Ovid’s Metamorphoses) in a dark, musty cave

hypnosis, special psychological state with certain physiological attributes, resembling sleep only superficially and marked by a functioning of the individual at a level of awareness other than the ordinary conscious state. This state is characterized by a degree of increased receptiveness and

Clark L. Hull: …studies formed the basis of Hypnosis and Suggestibility (1933).

sedative-hypnotic drug, chemical substance used to reduce tension and anxiety and induce calm (sedative effect) or to induce sleep (hypnotic effect). Most such drugs exert a quieting or calming effect at low doses and a sleep-inducing effect in larger doses. Sedative-hypnotic drugs tend to depress

Tom Petty: Hypnotic Eye, another Heartbreakers’ effort, topped the Billboard album chart in 2014.

malaria: The course of the disease: …the liver in a “hypnozoite” stage for months or even years before emerging to attack red blood cells and cause a relapse of the disease.

Gymnodinium: Sexual reproduction often results in hypnozygotes (thick-walled resting cysts) that can remain dormant in mud and other sediments until conditions are favourable for growth. Asexual reproduction is primarily through binary fission.

carpet moss, (genus Hypnum), genus of about 80 species of mosses (family Hypnaceae) that form dense green mats in many habitats throughout the world, especially on decaying wood in moist areas. A few species are aquatic. About 20 species occur in North America, though the taxonomy of the group is

feather moss, (Ptilium, formerly Hypnum, crista-castrensis), the only species of the genus Ptilium, it is a widely distributed plant of the subclass Bryidae that forms dense light green mats on rocks, rotten wood, or peaty soil, especially in mountain forests of the Northern Hemisphere. The erect

sheet moss, (Hypnum curvifolium), a species of carpet moss (family Hypnaceae). The names sheet moss and carpet moss refer to the growth pattern of the plants, which often form large carpetlike mats on rocks or soil. This species is sometimes used by florists in constructing flower

sodium: Principal compounds: Sodium thiosulfate (sodium hyposulfite), Na2S2O3, is used by photographers to fix developed negatives and prints; it acts by dissolving the part of the silver salts coated onto film which remain unchanged by exposure to light.

Aeolian mode: …its plagal (lower-range) form, the Hypoaeolian mode, had A as their finalis (the tone on which a piece in a given mode ends). The Ionian mode and its plagal counterpart, the Hypoionian, had their finalis on C. The pitch series of the Ionian mode matches that of the major scale.

hypoaldosteronism, abnormally low serum levels of aldosterone, a steroid hormone secreted by the adrenal gland. Hypoaldosteronism nearly always arises as a result of disorders in which the adrenal glands are destroyed. However, there does exist a disease in which defective aldosterone synthesis and

fruit processing: Storage: Hypobaric storage involves the cold storage of fruit under partial vacuum. Typical conditions include pressures as low as 80 and 40 millimetres of mercury and temperatures of 5 °C (40 °F). Hypobaric conditions reduce ethylene production and respiration rates; the result is an extraordinarily high-quality…

blastocyst: …layer of cells, called the hypoblast, between the inner cell mass and the cavity. These cells contribute to the formation of the embryonic endoderm, from which derive the respiratory and digestive tracts.

mollusk: External features: …epithelium called mucus tracts or hypobranchial glands, and the outlets for the digestive, excretory, and reproductive systems. A loss of the ctenidia (along with the mucus tracts) is seen in scaphopods, advanced gastropods, septibranch bivalves, and solenogasters.

muscle: Jawed fishes: The hypobranchial muscles of jawed fishes are straplike muscles running from the pectoral girdle to the structures of the visceral skeleton, the jaws, and the gill bars. Some muscles, such as the coracomandibularis, are specialized as jaw openers, although most of the work of jaw opening…

calcium deficiency: Severe calcium deficiency, or hypocalcemia, which is defined as a reduction of calcium levels in the bloodstream below a certain normal range, has its own clinical manifestations. The main syndrome is tetany, which involves sensations of numbness and tingling around the mouth and fingertips and painful aches and spasms…

hormone: Ultimobranchial tissue and calcitonin: …calcium in the blood (hypocalcemic action) when it rises above the normal level. Its secretion probably is regulated by a negative feedback relationship between the gland and the blood plasma. The hormone affects bone, which is an active tissue. It undergoes not only growth but also remodeling as it…

enamel: …instances, from genetic anomaly; (2) hypocalcification, in which there is insufficient calcium and a soft enamel is produced; this may result, for example, from excess fluorine in the diet. See also cementum; dentine.

cashew: …swollen stem (hypocarp), called the cashew apple. The cashew apple, which is an accessory fruit (e.g., not a true fruit), is about three times as large as the true fruit and is reddish or yellow. The true fruit has two walls, or shells. The outer shell is smooth, thin, and…

hypocaust, in building construction, open space below a floor that is heated by gases from a fire or furnace below and that allows the passage of hot air to heat the room above. This type of heating was developed by the Romans, who used it not only in the warm and hot rooms of the baths but also

earthquake: Principal types of seismic waves: …the Earth, is called the focus, or hypocentre. The point at the surface immediately above the focus is known as the epicentre.

orchid: Natural history: …or hood-shaped portion called the hypochile above; an elongate, sometimes fluted part, the mesochile; and a bucket-shaped epichile. The epichile is partially filled with water during the last few hours before the flower opens and for a short time afterward by two faucetlike organs located at the base of the…

poison: Inorganic compounds: Hypochlorites are often used as bleaching agents. In low concentrations, as in household bleaches, hypochlorites have little toxicity but may be irritating to tissues; they can, however, be corrosive at high concentrations. Cyanide ions poison the oxidative metabolic machinery of cells so that insufficient energy…

illness anxiety disorder, mental disorder characterized by an excessive preoccupation with illness and a tendency to fear or believe that one has a serious disease on the basis of the presence of insignificant physical signs or symptoms. Illness anxiety disorder is thought to be derived from the

The Imaginary Invalid, comedy in three acts by Molière, produced in 1673 and published in 1674 as Le Malade imaginaire. It was also translated as The Hypochondriac. Molière wrote the play while ill, and he collapsed during his own performance of the title role, that of Argan, a hypochondriac who

illness anxiety disorder, mental disorder characterized by an excessive preoccupation with illness and a tendency to fear or believe that one has a serious disease on the basis of the presence of insignificant physical signs or symptoms. Illness anxiety disorder is thought to be derived from the

dwarfism: Hypochondroplasia resembles achondroplasia except that the head is of normal size. Diastrophic dwarfism is characterized by progressive, crippling skeletal deformities. There is a high risk of death from respiratory failure during early infancy; thereafter the prospect of a normal life span is good. Intelligence is…

alcoholism: Chronic diseases: …resulting from vitamin C deficiency; hypochromic macrocytic anemia, caused by folate deficiency, vitamin B12 deficiency, or certain chemotherapeutic agents; and pernicious anemia, resulting from vitamin B12 deficiency. Severe open sores on the skin of alcoholic derelicts whose usual drink is the cheapest form of alcohol—low-quality fortified wines—are sometimes miscalled “wine…

blood disease: Anemia: …with hemoglobin; this is called hypochromic microcytic anemia. In still other cases of anemia, there is no significant alteration in the size, shape, or coloration of the red cells, a condition called normocytic anemia.

protozoan: Annotated classification: Hypochytriales Absorptive heterotrophs. Grow as chytridlike unicells; some also grow as hyphae. Typically parasitic or saprobic. Chrysophyceae (golden algae) Most freshwater. Have a unique feeding cup. Mixotrophy common; some taxa are strictly phagotrophic heterotrophs. Algal taxa possess 1 or 2 plastids per cell.

hypocoly, (Hypocolius ampelinus), Middle Eastern songbird believed by some authorities to be related to the waxwing (family Bombycillidae) but often separated as the sole member of the family Hypocoliidae (order Passeriformes). The hypocoly is a slim grayish bird, about 18 cm (7 inches) long, with

hypocoly, (Hypocolius ampelinus), Middle Eastern songbird believed by some authorities to be related to the waxwing (family Bombycillidae) but often separated as the sole member of the family Hypocoliidae (order Passeriformes). The hypocoly is a slim grayish bird, about 18 cm (7 inches) long, with

name: Forms of personal names: Hypocoristic forms of names are those that are used in familiar, friendly, or intimate situations (usually shortened or otherwise modified)—e.g., Tom for Thomas, Jim for James. Some of these forms are also used as given names, particularly in the United States.

Addison disease, rare disorder defined by destruction of the outer layer of the adrenal glands, the hormone-producing organs located just above the kidneys. Addison disease, a kind of autoimmune disease, is rare because it only occurs when at least 90 percent of the adrenal cortex is destroyed. In

angiosperm: Stems: …a transition region called the hypocotyl. In the developing embryo, the hypocotyl is the embryonic axis that bears the seedling leaves (cotyledons).

fungus: Annotated classification: Order Hypocreales Parasitic or pathogenic on plants, may cause canker formation; when present, perithecia and stromata are brightly coloured, soft, fleshy, or waxy; asci borne in a basal layer among apical paraphyses; included in subclass Hypocreomycetidae; example genera include Hypocrea, Nectria, Cordyceps, Claviceps, and Niesslia. Order…

narcolepsy: …of a hormone known as hypocretin (also known as orexin), which promotes wakefulness. The loss of hypocretin may in turn be linked to an underlying autoimmune disorder in which immune cells target the hormone for destruction. In some persons, autoimmunity against hypocretin is suspected to occur as a result of…

malformation: Somatic characters: …as fingers or toes (polydactyly, hypodactyly [ectrodactyly], brachydactyly), is a frequent anomaly in man and other mammals. In many analyzed cases it has been shown to result from the inheritance of an abnormal gene that produces a localized disturbance of a growth process in the embryo. In the rabbit a…

fern: Annotated classification: Family Hypodematiaceae Small family of 2 genera, Hypodematium (about 20 species) and Leucostegia (2 species). Family Lomariopsidaceae Plants in soil, on rocks, or climbing (hemiepiphytic); rhizomes short- to long-creeping, sometimes with runners, scaly; leaves mostly 1 time pinnately compound, the leaflets often

warble fly: …bot, flies Hypoderma lineatum and H. bovis are large, heavy, and beelike. The females deposit their eggs on the legs of cattle. The larvae penetrate the skin, migrate through the body for several months, and produce a characteristic lump, or warble, on the animal’s back. The warble contains a hole,…

warble fly: The warble, or bot, flies Hypoderma lineatum and H. bovis are large, heavy, and beelike. The females deposit their eggs on the legs of cattle. The larvae penetrate the skin, migrate through the body for several months, and produce a characteristic lump, or warble, on the animal’s back. The warble…

warble fly: Oedemagena tarandi is another warble fly that causes economic losses of leather, meat, and milk in reindeer herds.

blood transfusion: Transfusion procedures and blood storage: …vein by means of a hypodermic syringe and is passed through a plastic tube to a collection bag or bottle to which sodium citrate has been added in order to prevent the blood from clotting. In transfusing blood into the recipient, donor blood of the appropriate type is passed by…

tree: Leaf adaptations: …and hairy, often with additional hypodermis and covered by a cuticle and epicuticular wax. Stomates are smaller, more closely spaced, sunken below the leaf surface, and covered with wax or hairs or both. Salt glands and water-storage cells are present in some species.

adipsia, rare disorder characterized by the lack of thirst even in the presence of dehydration. In adipsia the brain’s thirst centre, located in the hypothalamus, is damaged. People with adipsia have little or no sensation of thirst when they become dehydrated. These people must be instructed, even

Hypodorian mode, in music, second of the eight medieval church modes. See church

blood disease: Afibrinogenemia: Afibrinogenemia, or hypofibrinogenemia, refers to a reduction in the amount of the clotting factor fibrinogen in the blood. This is seen in rare instances as an inherited disorder, but more commonly it is found as part of the syndrome of disseminated intravascular coagulation (see…

human endocrine system: Endocrine hypofunction and receptor defects: …in hormone production, known as hypofunction, is required to maintain homeostasis. One example of hypofunction is decreased production of thyroid hormones during starvation and illness. Because the thyroid hormones control energy expenditure, there is survival value in slowing the body’s metabolism when food intake is low. Thus, there is a…

gamma globulin: …it—conditions called, respectively, agammaglobulinemia and hypogammaglobulinemia—have frequently recurring infections because of their inability to develop adequate immunity to infectious diseases. See also antibody.

angiosperm: Seedlings: In hypogeous germination, the hypocotyl remains short and the cotyledons do not emerge from the seed but rather force the radicle and epicotyl axis to elongate out of the seed coat. The seed, with the enclosed cotyledons, remains underground, and the epicotyl grows up through the…

angiosperm: Seedlings: In hypogeous germination, the hypocotyl remains short and the cotyledons do not emerge from the seed but rather force the radicle and epicotyl axis to elongate out of the seed coat. The seed, with the enclosed cotyledons, remains underground, and the epicotyl grows up through the…

human nervous system: Hypoglossal nerve (CN XII or 12): The hypoglossal nerve innervates certain muscles that control movement of the tongue. From the hypoglossal nucleus in the medulla oblongata, general somatic efferent fibers exit the cranial cavity through the hypoglossal canal and enter the neck in close proximity…