69 résultats pour "skin"
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Skin.
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INTRODUCTION
Skin, outer body covering of an animal. The term skin
III SKIN APPENDAGES In humans, the skin appendages, or structures embedded in the skin, include hair, nails, and several types of glands. Glands are groups of cells that produce andsecrete substances needed by other parts of the body. In other vertebrates, the skin appendages include scales (in fish and reptiles) and feathers (in birds). Together,the skin and the skin appendages are known as the integumentary system of the body. A Hair Hair is a distinguishing characteristic of mammals, a gro...
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First Aid.
IV SEVERE BLEEDING The presence of blood over a considerable area of a person’s body does not always indicate severe bleeding. The blood may ooze from multiple small wounds or besmeared, giving the appearance of more blood than is actually present. The rate at which blood is lost from a wound depends on the size and kind of blood vesselruptured. Bright red, spurting blood indicates injury to an artery while welling or steadily flowing, dark red blood indicates injury to a vein. Welling or spur...
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Comparative Anatomy.
In comparing two species, anatomists have to be careful to differentiate between homologous structures, which are ones that have evolved from a shared ancestor, andanalogous structures, which have developed from different origins. Homologous structures are built on the same underlying plan. A human arm, a bat’s wing, and awhale’s flipper look quite different from the outside, but the bones inside reveal that these limbs all have the same basic structure. Analogous structures, by contrast,often l...
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Race - biology.
distributed as a cline, generally varying along a north-south line. Skin color is lightest in northern Europeans, especially in those who live around the Baltic Sea, andbecomes gradually darker as one moves toward southern Europe, the Mediterranean, the Middle East, and into northern Africa and northern subtropical Africa. Skin isdarkest in people who live in the tropical regions of Africa. The lack of clear-cut discontinuities makes any racial boundary based on skin color totally arbitrary. Sim...
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Frog (animal).
which means that their body temperature depends on the temperature of the surrounding environment. Few species can tolerate temperatures below 4°C (40°F) orabove 40°C (104°F), and many species can survive only within a narrower range of temperatures. In addition, frogs’ thin, moist skin offers little protection againstwater loss, and when on land the animals must guard against drying out. Many frogs are active at night because temperatures are cooler and humidity is higher thanduring the day. In...
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Frog (animal) - biology.
which means that their body temperature depends on the temperature of the surrounding environment. Few species can tolerate temperatures below 4°C (40°F) orabove 40°C (104°F), and many species can survive only within a narrower range of temperatures. In addition, frogs’ thin, moist skin offers little protection againstwater loss, and when on land the animals must guard against drying out. Many frogs are active at night because temperatures are cooler and humidity is higher thanduring the day. In...
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Vitamin.
Vitamin B 1, or thiamine, promotes the metabolism of carbohydrates, enabling these nutrients to release their energy. Thiamine also plays a role in the functioning of the nervous system, muscles, and heart. The body does not store thiamine and people who are malnourished may develop thiamine deficiency. Mild thiamine deficiency cancause fatigue, muscle weakness, and loss of appetite. Severe thiamine deficiency causes beriberi, a disease characterized by muscle weakness, swelling of the heart,and...
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Birth Control.
without a prescription and used alone or with a condom, diaphragm, or cervical cap. Spermicides used alone must be inserted deep into the vagina before each act ofintercourse and a woman should not douche for six to eight hours after intercourse. With typical use, spermicides used alone are effective in preventing pregnancyabout 74 percent of the time. They may cause an allergic reaction such as irritation of the vagina or penis. B Intrauterine Device The intrauterine device (IUD) is a small pl...
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Amphibian (animal) - biology.
strong enough to kill potential predators. C Hearing, Vision, and Vocalizations Amphibians rely on their senses to find food and evade predators. Amphibians lack external ears but have well-developed internal ears. Hearing is most acute in frogs,which typically have a middle ear cavity for transferring sound vibrations from the eardrum, or tympanum, to the inner ear. Frogs and toads also use their keen hearingin communicating with one another. Using a true voice box, or larynx, and a large, exp...
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Ear.
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INTRODUCTION
Ear, organ of hearing and balance. Only vertebrates, or animals
line or rotates in any direction. Each canal also contains sensory areas with sensory hair cells that project into a cone-shaped cap of gelatin. Two of the semicircularcanals are in a vertical position and are used to detect vertical movement, such as jumping or falling. The third canal is horizontal and detects horizontal movement,such as turning or spinning. The action of the canals depends on the inertia of the fluid inside. When the motion of the body changes, the fluid lags behind, causing...
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Aboriginal Australians - History.
Until Europeans began to settle in Australia in 1788, the Aboriginal way of life was supported by hunting, gathering, and fishing. Like other hunting and gatheringpeoples, Aboriginal people had an extremely detailed knowledge of their environment, especially plant ecology and animal behavior. The deep connection betweenAboriginal people and the natural world influenced every part of their culture, including their food gathering, tools, trade, religion, art, music, language, and socialorganizatio...
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Rhinoceros - biology.
Male and female rhinos have a similar physical appearance, although male rhinos are usually larger than females, with the size difference varying between species. Inthe wild, some rhinos probably live into their late 40s, and they have survived into their 30s in captivity. IV TYPES OF RHINOCEROSES Until recently, mammalogists divided the rhinoceros family into three subfamilies, each with different characteristics. Scientists now believe that living rhinos belong to asingle subfamily, although...
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Drug.
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INTRODUCTION
Drug, substance that affects the function of living cells, used
normalizing chemical activity in the emotional centers of the brain. Antianxiety drugs, also referred to as tranquilizers, treat anxiety by decreasing the activity in theanxiety centers of the brain. Sedative-hypnotic drugs are used both as sedatives to reduce anxiety and as hypnotics to induce sleep. Sedative-hypnotic drugs act by reducing brain-cell activity.Stimulant drugs, on the other hand, increase neuronal (nerve cell) activity and reduce fatigue and appetite. Analgesic drugs reduce pain...
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Elephant - biology.
B Trunk An elephant's nose and upper lip are combined in a long, limber trunk, an exceptionally supple appendage with an estimated 150,000 muscles. The versatile trunk actslike a hand for grasping low-growing shrubs and other food and placing it into the mouth; an arm for breaking off tree branches; or a snorkel for breathing when theelephant's body is submerged. Elephants also use their trunks to suck up water and squirt it into their mouths for drinking or over their bodies for bathing. Nostr...
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Turtle.
Turtles use their jaws to cut and handle food. Instead of teeth, a turtle’s upper and lower jaws are covered by horny ridges, similar to a bird’s beak. Meat-eating turtlescommonly have knife-sharp ridges for slicing through their prey. Plant-eating turtles often have ridges with serrated edges that help them cut through tough plants.Turtles use their tongues in swallowing food, but unlike many other reptiles, such as chameleons, they cannot stick out their tongues to capture food. C Limb Structu...
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Turtle - biology.
Turtles use their jaws to cut and handle food. Instead of teeth, a turtle’s upper and lower jaws are covered by horny ridges, similar to a bird’s beak. Meat-eating turtlescommonly have knife-sharp ridges for slicing through their prey. Plant-eating turtles often have ridges with serrated edges that help them cut through tough plants.Turtles use their tongues in swallowing food, but unlike many other reptiles, such as chameleons, they cannot stick out their tongues to capture food. C Limb Structu...
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Dinosaur - biology.
The behavior of dinosaurs was governed by their metabolism and by their central nervous system. The dinosaurs’ metabolism—the internal activities that supply thebody’s energy needs—affected their activity level. It is unclear whether dinosaurs were purely endothermic (warm-blooded), like modern mammals, or ectothermic (cold-blooded), like modern reptiles. Endotherms regulate their body temperature internally by means of their metabolism, rather than by using the temperature oftheir surroundin...
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Virus (life science) - biology.
RNA into DNA earned them their name because this process is the reverse of the usual transfer of genetic information, from DNA to RNA.) The DNA form of theretrovirus genome is then integrated into the cellular DNA and is referred to as the provirus. The viral genome is replicated every time the host cell replicates its DNA and is thus passed on to daughter cells. Hepatitis B virus can also transcribe RNA to DNA, but this virus packages the DNA version of its genome into virus particles. Unlike...
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Inuit.
VII HOUSING, TRANSPORTATION, AND CLOTHING Inuit homes are of two kinds: walrus or sealskin tents for summer and huts or houses for winter. Winter houses are usually made of stone, with a driftwood orwhalebone frame, chinked and covered with moss or sod. The entrance is a long, narrow passage just high enough to admit a person crawling on hands and knees.During long journeys some Canadian Inuit build igloos, winter houses of snow blocks piled in a dome shape (the term igloo comes from the I...
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Snake (reptile).
in their heads that conduct sound. They are able to hear low-frequency sounds and to sense vibrations that travel through the ground or water. The majority of snakeshave good eyesight, especially for detecting moving objects, although most burrowing snakes can only distinguish between light and dark. Pit vipers, boas, and pythons have an unusual adaptation for detecting warm-blooded prey and predators. On the heads of these snakes are small pits lined with cellsthat are extremely sensitive to he...
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Fruit - biology.
from a flower with several pistils. The ovary may have a single compartment, or carpel, which houses the ovule or ovules. Or the ovary may consist of two or morecarpels, each of which may contain one or more ovules. A drupe develops from an ovary with a single carpel and is characterized by an edible exocarp and mesocarp and an inedible, hard endocarp, or pit that encloses asingle seed. Cherries, peaches, apricots, and plums are examples of drupes. Almonds also are classified as drupes, but in a...
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Native American Architecture.
B Relationship to the Universe and Nature A more profound difference between European American and Native American perceptions lay in how human beings saw themselves in relationship to the universe andin what they believed their responsibilities were to the natural world and to each other. Most European Americans saw themselves as separate from creation andadversaries of nature, ever struggling to conquer and subdue nature and force it to yield to their will. Native Americans saw themselves as...
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Seal (mammal) - biology.
remote lakes by swimming thousands of kilometers up rivers from the Arctic Ocean. A few other species such as ringed seals and harbor seals have been found livingyear-round in lakes and rivers near the coasts of Russia, Canada, and Alaska. IV DIET OF SEALS Most seals eat fish and sometimes squid. The leopard seal, an Antarctic species, may have the most diverse diet of all, commonly hunting penguins and other seabirds,smaller seals, as well as fish, squid, krill (small shrimplike crustaceans),...
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Diseases of Animals.
infected animal. It may also spread in milk or in garbage that contains contaminated meat. Typical symptoms include blisters that appear on the mouth and feet;animals may become lame when their hooves degenerate. Canine distemper is a highly contagious disease caused by the paramyxovirus, which is transmitted in discharges from the nose and eyes. Symptoms begin with fever,malaise, and nasal and ocular discharges and may progress to convulsions and other nervous system disorders. Parvoviruses aff...
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Python (snake) - biology.
pythons are prey for monitor lizards, crocodiles, storks, eagles, and predatory mammals ranging from hyenas to leopards and other cats depending on the region. V PYTHONS AND HUMANS Modern humans have lived alongside pythons for thousands of years. The giant species have been treated with both reverence and fear. Pythons have been widelyassociated with fertility, water, and the Earth. Some African tribes have worshiped pythons as protective spirits. Among Aboriginal Australians the Rainbow Serpe...
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Surgery.
III SURGICAL PROCEDURES Surgical procedures are classified as optional, required, elective, urgent, and emergent based on the patient’s medical condition. Optional surgery consists of operationsthat are not required but which the patient chooses to undergo as with some types of cosmetic surgery. Required surgery is performed when only surgery will correct aproblem—such as cataracts—but the surgery can be delayed for a period of weeks or months. Elective surgical procedures usually involve cond...
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Native American Art.
folding, braiding or weaving, could also be sewn onto the hide. The production of decorated clothing and bags increased after contact with Europeans as a greater variety of textiles and other materials became available throughtrade. Imported glass beads inspired native women, who quickly adapted quillwork techniques for the creation of beaded apparel. European curvilinear and floraldesigns of the 19th century proved as meaningful for the native women who worked with them as they were for the non...
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Jaguar (animal) - biology.
scientists have speculated that the jaguar’s robust canine teeth and enormously powerful bite developed specifically to pierce the armor of these reptiles. After killing a large animal, a jaguar will usually drag the carcass into dense cover before beginning to eat. If the kill is made in an open area, jaguars often drag theirprey for considerable distances. On one occasion, a jaguar killed a cow on the edge of a river and swam 790 m (2,600 ft) across the river carrying the cow. Unlike the other...
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Reproductive System.
in which the young develop, and a thinner channel, the vagina, which opens exteriorly. V GENITALS In animals that lay their eggs and discharge their sperm into water, the spermatozoa reach the eggs by chemical attraction; the eggs of individuals of a species attractonly the sperm of members of the same species. When eggs and sperm are deposited at great distances from each other, the number of eggs fertilized is small. Manyamphibians and aquatic vertebrates solve this problem by attaching thems...
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Hercules (mythology)
I
INTRODUCTION
Pollaiuolo's Hercules et Antaeus
In a wrestling match, Hercules triumphed over the mighty giant Antaeus, who received his strength from his mother, the
Earth goddess Gaia.
Pollaiuolo’s Hercules and the HydraAmong his 12 labors, the mythological hero Hercules had to kill the nine-headed Hydra. Each time Hercules cut off onehead, two more grew in its place. Hercules solved the problem by, as soon as he cut off one head, burning with a torchthe spot where it had been to stop its regrowth. Hercules and the Hydra (about 1460, Uffizi, Florence, Italy) was paintedby Italian artist Antonio Pollaiuolo. Hercules is shown wearing the skin of the Nemean lion, which he had kil...
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Cancer (medicine).
unable to repair the DNA damage, p53 instructs the cell to undergo programmed cell death, or apoptosis , putting a stop to runaway cell division before it starts. Programmed cell death is a normal part of cell life and is tightly controlled by many genes, primarily p53. In a cancerous cell, one or more mutations prevent these genes from doing their jobs. When mutated, p53 allows a cell to continue to divide, even with damaged DNA.This can lead to additional mutations in proto-oncogenes or tumor...
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Smoking.
causes about 20 times the number of deaths in the United States than all other addictive drugs combined. Smoking cessation methods are plentiful, and many books and products are available to help an individual stop smoking. Many smokers turn to group help because ofthe support and understanding provided by other former smokers or people trying to quit. Most successful group-help techniques involve a challenge and rewardsystem that also bolsters the self-discipline of the former smoker. A number...
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From Bulfinch's Mythology: Hercules - anthology.
'…amidst the gardens fairOf Hesperus and his daughters three,That sing about the golden tree.' The poets, led by the analogy of the lovely appearance of the western sky at sunset, viewed the west as a region of brightness and glory. Hence they placed in it theIsles of the Blest, the ruddy Isle Erytheia, on which the bright oxen of Geryon were pastured, and the Isle of the Hesperides. The apples are supposed by some to bethe oranges of Spain, of which the Greeks had heard some obscure account...
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Canadian Architecture
I
INTRODUCTION
L'Anse aux Meadows
In around ad 1000 Norse Vikings sailed from Greenland to North America and set up a village on the tip of what is now
the island of Newfoundland's Great Northern Peninsula.
IglooSome Inuit peoples in the Arctic regions of Canada live in domed houses of snow, or igloos, which provide good insulationand protection from wind. The word igloo comes from the Inuit iglu, meaning “house.”George Holton/Photo Researchers, Inc. Canada’s original inhabitants are known as the First Nations. At the time of European arrival, about 40 nations were scattered across Canada. Many of them lived alongthe coasts, where they could fish. These nations can be classified into five major gro...
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Antibiotics.
In some species of bacteria the cell wall consists primarily of a thick layer of peptidoglycan. Other species have a much thinner layer of peptidoglycan and an outer aswell as an inner membrane. When bacteria are subjected to Gram's stain, these differences in structure affect the differential staining of the bacteria with a dye calledgentian violet. The differences in staining coloration (gram-positive bacteria appear purple and gram-negative bacteria appear colorless or reddish, depending on t...
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Anatomy.
The body defends itself against foreign proteins and infectious microorganisms by means of a complex dual system that depends on recognizing a portion of the surfacepattern of the invader. The two parts of the system are termed cellular immunity, in which lymphocytes are the effective agent, and humoral immunity, based on theaction of antibody molecules. When particular lymphocytes recognize a foreign molecular pattern (termed an antigen), they release antibodies in great numbers; other lymphocy...
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Butterflies and Moths - biology.
The smallest butterflies are certain blues that have wingspans of a mere 0.7 cm (0.25 in). The largest are the female giant birdwings of Papua New Guinea, whichmeasure up to 30 cm (12 in) across. Moths range in size from tiny Microlepidoptera, several groups of small moths with wings no more than 0.16 cm (0.06 in) across, togiant silk moths, such as the atlas moth, which may exceed 30 cm (12 in) in wingspan. IV REPRODUCTION AND LIFE CYCLE Butterflies locate potential mates by sight, identifyin...
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Acquired Immunodeficiency Syndrome.
child transmission is particularly prevalent in Africa. D Misperceptions About HIV Transmission The routes of HIV transmission are well documented by scientists, but health officials continually grapple with people’s unfounded fears concerning the potential for HIVtransmission by other means. HIV differs from other infectious viruses in that it dies quickly if exposed to the environment. No evidence has linked HIV transmission tocasual contact with an infected person, such as a handshake, huggi...
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Native Americans of North America.
addition to smallpox and measles, explorers and colonists brought a host of other diseases: bubonic plague, cholera, typhoid fever, scarlet fever, pleurisy, mumps,diphtheria, pneumonia, whooping cough, malaria, yellow fever, and various sexually transmitted infections. Despite the undisputed devastation wreaked on Indian populations after European contact, native populations showed enormous regional variability in their response todisease exposure. Some peoples survived and, in some cases, even...
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Native Americans of North America - Canadian History.
addition to smallpox and measles, explorers and colonists brought a host of other diseases: bubonic plague, cholera, typhoid fever, scarlet fever, pleurisy, mumps,diphtheria, pneumonia, whooping cough, malaria, yellow fever, and various sexually transmitted infections. Despite the undisputed devastation wreaked on Indian populations after European contact, native populations showed enormous regional variability in their response todisease exposure. Some peoples survived and, in some cases, even...
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Native American Architecture
I
INTRODUCTION
Native American Architecture, traditional architecture of the peoples of who lived in North America before Europeans arrived.
Mound Builders who resided in the area.John Elk III/Bruce Coleman, Inc. Another mound building culture, named Hopewell, also appears to have originated in Ohio but expanded west to Iowa, Kansas, and Oklahoma, south to Louisiana,Mississippi, and Alabama, east to Georgia and the Appalachian Mountains, and north to Wisconsin, Michigan, and lower Ontario in Canada. The Hopewell culture lastedfrom about 200 BC to 400 AD. Hopewell people built large, linear mounds to create enclosures in geometrical...
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Mammal - biology.
On land, mammals live in many different habitats, and at a wide range of altitudes. Many mammals dig burrows as refuges or as places to raise their young, but somehave developed a largely subterranean lifestyle, feeding on small animals or plant roots beneath the soil's surface. These animals, including moles and mole-rats, digthrough the ground either with spadelike front paws or with their teeth, and they detect danger by being highly sensitive to vibrations transmitted through the soil.Most m...
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Shark - biology.
Sharks have two-chambered hearts that are relatively small compared to the rest of their bodies. Blood flows from the heart to the gills, where it collects oxygen fromwater and then distributes it to the other organs and tissues. The small heart produces weak blood pressure, and many sharks must swim continuously to create themuscular contractions needed to circulate blood throughout their bodies. Most sharks are cold-blooded—that is, they do not generate heat by digesting food. Instead, the bod...
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Seals.
noises to find mates and scare away rivals. Some types of seals sing songs that last more than a minute. ARE SEALS ENDANGERED? Large sharks and killer whales hunt and eat seals. Polar bears kill seals on land and on ice in the Arctic.But people are the biggest threat to seals. People have hunted seals for food, skins, and blubber. The northern elephant seal has nearly died out. Hawaiian and Mediterranean monk seals are alsoendangered, and a third type of monk seal is already extinct. Many countr...
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I understood him.
HAPPINESS, HAPPINESS INTERVIEWER. Canyoudescribe theevents ofthat morning? TOMOYASU. Ileft home withmydaughter, Masako.Shewas onher way towork. Iwas going tosee afriend. Anair-raid warning wasissued. Itold Masako Iwas going home. Shesaid, "I'mgoing tothe office." Idid chores andwaited forthe warning tobe lifted. I folded thebedding. Irearranged thecloset. Icleaned thewindows withawet rag. There wasaflash. Myfirst thought was that itwas theflash from acamera. Thatsounds soridiculous now.Itpierc...
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Fur Trade in North America - Canadian History.
Injured by the competition from the North West Company, the Hudson’s Bay Company changed its methods in the late 18th century and began extending its operationsinland. After a period of intense and often violent conflict, the two companies merged in 1821 under the charter of the Hudson’s Bay Company. The trade monopoly andpower to govern that had been originally given to Hudson’s Bay in 1670 were extended to all British-held territory west of Rupert’s Land. The company dominated mostof present-d...
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Human Disease.
disease can be transmitted through food infected with mutated proteins. B Spread of Infectious Disease Some pathogens are spread from one person to another by direct contact. They leave the first person through body openings, mucous membranes, and skin wounds,and they enter the second person through similar channels. For example, the viruses that cause respiratory diseases such as influenza and the common cold are spreadin moisture droplets when an infected person coughs or sneezes. A hand that...
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Essay racism
peoples are used and the creation of communities. Racism is also a problem in employment. Most of the time, the white people are always hired first. The most well-known example is the presidential in the U.S. nobody who has a skin color became president of the United States before B. Obama in 2009. However, it shows that the Americans are less racist but it means that it took time for them to finally trust and see that we are all equal no matter what. To conclude, racism is not an ability that p...
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Animals.
All animals must breathe oxygen to stay alive. They must breathe out a waste gas called carbon dioxide. Some animals breathe through lungs. Lungs take oxygen out of air. Cattle, dogs, cats, whales, people,and other mammals breathe through lungs. Birds and reptiles also breathe air through lungs. Lungs cannot take air from water. Seals, whales, dolphins, and other mammals that live in waterbreathe through lungs. They can stay underwater a long time because they can hold their breath for along tim...
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Being Brown
eurocentriques du monde, une joie qui vient du fait d'être parfaitement centré culturellement… » D. Writing : Priya dislikes living in America, she thinks it is a land of inequalities. She praises Indian values that seem better according to her. Her father disagrees with her, he praises American values, and seems to be happy with all the comfort he could get in the United States. Both sides have positive and negative aspects. First, about Priya's point of view. She is right when she says...