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A direct flight from Lima to Cuzco was diverted to Arequipa due to unexpected bad weather. 163 passengers were on the flight when it finally arrived at Cuzco. How many passengers boarded the flight in Arequipa?1. When the plane took off from Lima, 184 people were on board.2. 30 people chose to disembark at Arequipa and did not re-board the flight.
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A retailer buys t-shirts from a wholesaler in lots of 25 t-shirts each. What is the wholesale price of a lot of t-shirts?1. The retailer sells a single t-shirt for $4.80.2. The retailer sells t-shirts at 20 percent above the wholesale price.
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What is the area of triangle R?1. The base of triangle R is 15.2. The ratio of the altitude dropped from the vertex opposite the base is related to the base of R is 5 to 1.
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A pharmacy offers customers both a patented and a generic version of a certain drug. The pharmacy makes a profit of 20 percent of the cost on every box of the patented version, and it makes a profit of 5 percent of the cost on every box of the generic version. During a certain time period, which version of the drug yields a greater dollar profit to the pharmacy?1. The pharmacy pays more to the wholesaler per box for the patented version than for the generic version.2. The pharmacy sells 30 percent more of the generic version of the drug by weight than the patented version.
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How many seconds long is time period U if U can be no longer than a day?1. Time period U lasts from 13:59:00 until 14:02:00.2. Time period U lasts from 1:59:00 pm until 2:02:00 pm.
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The surface area of a parallelepiped P is?1. The volume of P is 24 square meters.2. The height of P is 200 centimeters.
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In 1942, was the number of people drafted to the army of Country X greater than three times the number of people drafted to the army of Country Y?1. In 1942, there were approximately 0.7 million more people drafted to the army of Country X then those drafted to the army of Country Y.2. In 1942, the 300,000 Adventist Christians made up 20 percent of the draft to the army of Country X, and the 141,000 Evangelists made up 30 percent of the draft to the army of Country Y.
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How many prime numbers are there strictly greater than 5 and less than the integer k?1. 20 < k < 342. 17 < k < 33
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Is uv > 0?1.$$({u}^{2})({v}^{3})<{0}$$2.$${u}({v}^{2})<{0}$$
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John, Pete, and Tim are running 100-meter races to prepare for a championship. Each of the runners won at least one of the heats. Which one of the three runners won the most races?1. Tim won $$\frac{3}{7}$$ as many races as Pete.2. Pete won $$\frac{7}{3}$$ as many races as John.
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The average (arithmetic mean) of a professor's salary at University M is s. Is the average salary of a professor at University D at least 25 percent higher than that for a professor at University M?1. At University M, the budget allocates $3,500,000 for faculty remuneration.2. At University D, the budget allocates $6,000,000 for faculty's salaries.
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A yacht club conducts a training race every Friday and Sunday during the summer months weather permitting. If the club was able to conduct a race every Friday and Sunday in the month of July, how many races were there that month?1. There were five Tuesdays in the month.2. The twenty-fifth of July was a Thursday.
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Is $$\varepsilon$$ equal to the average (arithmetic mean) of $$\zeta,\eta,\psi,\xi$$ and $$\upsilon$$?1.$$\upsilon+\eta+\psi+\varepsilon+\upsilon=5\xi$$2.$$\frac{\zeta+\eta+\psi+\varepsilon+\upsilon}{10}=\frac{\xi}{2}$$
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What is the value of t?1.$${T}({T}-{1})^{2}={4}{T}$$2.T is an integer.
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During the nineteenth century, occupational information about women that was provided by the United States census-a population count conducted each decade-became more detailed and precise in response to social changes. Through 1840, [hl:5]simple[/hl:5] enumeration by household mirrored a home-based agricultural economy and hierarchical social order: the head of the household (presumed male or absent) was specified by name, whereas other household members were only indicated by the total number of persons counted in various categories, including occupational categories. Like farms, most enterprises were family-run, so that the census measured economic activity as an attribute of the entire household, rather than of individuals.The 1850 census, partly responding to antislavery and women's rights movements, initiated the collection of specific information about each individual in a household. Not until 1870 was occupational information analyzed by gender: the census superintendent reported 1.8 million women employed outside the home in "gainful and reputable occupations". In addition, he arbitrarily attributed to each family one woman "keeping house". Overlap between the two groups was not calculated until 1890, when the rapid entry of women into the paid labor force and social issues arising from industrialization were causing [hl:1]women's advocates and women statisticians[/hl:1] to press for more thorough and accurate accounting of women's occupations and wages.
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Australian researchers have discovered electroreceptors (sensory organs designed to respond to electrical fields) clustered at the tip of the spiny anteater's snout. The researchers made this discovery by exposing small areas of the snout to extremely weak electrical fields and recording the transmission of resulting nervous activity to the brain. While it is true that [hl:6]tactile receptors, another kind of sensory organ on the anteater's snout, can also respond to electrical stimuli, such receptors do so only in response to electrical field strengths about 1,000 times greater than those known to excite electroreceptors.[/hl:6]Having discovered the electroreceptors, researchers are now investigating how anteaters utilize such a sophisticated sensory system. In one behavioral experiment, researchers successfully trained an anteater to distinguish between two troughs of water, one with a weak electrical field and the other with none. Such evidence is consistent with researchers' [hl:3]hypothesis that anteaters use electroreceptors to detect electrical signals given off by prey[/hl:3]; however, researchers as yet have been unable to detect electrical signals emanating from termite mounds, where the favorite food of anteaters live. Still, researchers have observed anteaters breaking into a nest of ants at an oblique angle and quickly locating nesting chambers. This ability to quickly locate unseen prey suggests, according to the researchers, that the anteaters were using their electroreceptors to locate the nesting chambers.
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In 1896 a Georgia couple suing for damages in the accidental death of their two-year-old was told that since the child had made no real economic contribution to the family, there was no liability for damages. In contrast, less than a century later, in 1979, the parents of a three-year-old sued in New York for accidental-death damages and won an award of $750,000.The transformation in social values implicit in juxtaposing these two incidents is the subject of Viviana Zelizer's excellent book, Pricing the Priceless Child. During the nineteenth century, she argues, the concept of the "useful" child who contributed to the family economy gave way gradually to the present-day notion of the "useless" child who, though producing no income for, and indeed extremely costly to, its parents, is yet considered emotionally "priceless." Well established among segments of the middle and upper classes by the mid-1800's, this new view of childhood spread throughout society in the late nineteenth and early twentieth centuries as reformers introduced child labor regulations and compulsory education laws predicated in part on the assumption that a child's emotional value made child labor taboo.For Zelizer the origins of this transformation were many and complex. The gradual erosion of children's productive value in a maturing industrial economy, the decline in birth and death rates, especially in child mortality, and the development of the companionate family (a family in which members were united by explicit bonds of love rather than duty) were all factors critical in changing the assessment of children's worth. Yet "expulsion of children from the 'cash nexus; ... although clearly shaped by profound changes in the economic, occupational, and family structures," Zelizer maintains, "was also part of a cultural process of 'sacralization' of children's lives." Protecting children from the crass business world became enormously important for late nineteenth-century middle-class Americans, she suggests; this sacralization was a way of resisting what they perceived as the relentless corruption of human values by the marketplace.In stressing the cultural determinants of a child's worth, Zelizer takes issue with practitioners of the new "sociological economics," who have analyzed such traditionally sociological topics as crime, marriage, education, and health solely in terms of their economic determinants. Allowing only a small role for cultural forces in the form of individual "preferences;' these sociologists tend to view all human behavior as directed primarily by the principle of maximizing economic gain. Zelizer is highly critical of this approach, and emphasizes instead the opposite phenomenon: the power of social values to transform price. As children became more valuable in emotional terms, she argues, their "exchange" or "surrender" value on the market, that is, the conversion of their intangible worth into cash terms, became much greater.
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Coral reefs are one of the most fragile, biologically complex, and diverse marine ecosystems on Earth. This ecosystem is one of the fascinating paradoxes of the biosphere:how do clear, and thus nutrient-poor, waters support such prolific and productive communities? Part of the answer lies within the tissues of the corals themselves. Symbiotic cells of algae known as zooxanthellae carry out photosynthesis using the metabolic wastes of the corals, thereby producing food for themselves, for their coral hosts, and even for other members of the reef community. This symbiotic process allows organisms in the reef community to use sparse nutrient resources efficiently.Unfortunately for coral reefs, however, a variety of human activities are causing worldwide degradation of shallow marine habitats by adding nutrients to the water. Agriculture, slash-and-burn land clearing, sewage disposal, and manufacturing that creates waste by-products all increase nutrient loads in these waters. Typical symptoms of reef decline are destabilized herbivore populations and an increasing abundance of algae and [hl:3]filter-feeding animals[/hl:3]. Declines in reef communities are consistent with observations that nutrient input is increasing in direct proportion to growing human populations, thereby threatening reef communities sensitive to subtle changes in nutrient input to their waters.
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Although genetic mutations in bacteria and viruses can lead to epidemics, some epidemics are caused by bacteria and viruses that have undergone no significant genetic change. In analyzing the latter, scientists have discovered the importance of social and ecological factors to epidemics. Poliomyelitis, for example, emerged as an epidemic in the United States in the twentieth century by then, modern sanitation was able to delay exposure to polio Until adolescence or adulthood, at which time polio infection produced paralysis. Previously, infection had occurred during infancy, when it typically 9rovided lifelong immunity without paralysis. Thus, the hygiene that helped prevent typhoid epidemics indirectly fostered a paralytic polio epidemic. Another example is lyme disease, which is caused by bacteria that are transmitted by deer ticks. It occurred only sporadically during the late nineteenth century but has recently become prevalent in parts of the United States, largely due to an increase in the deer population that occurred simultaneously with the growth of the suburbs and increased outdoor recreational activities in the deer's habitat. Similarly, an outbreak of dengue hemorrhagic fever became an epidemic in Asia in the 1950's because of ecological changes that caused Aedes aegypti, the mosquito that transmits the dengue virus, to proliferate.The stage is now set in the United States for a dengue epidemic because of the inadvertent introduction and wide dissemination of another mosquito, Aedes albopictus.
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Homeostasis, an animal's maintenance of certain internal variables within an acceptable range, particularly in extreme physical environments, has long interested biologists. The desert rat and the camel in the most water-deprived environments, and marine vertebrates in an all-water environment, encounter the same regulatory problem：maintaining adequate Internal fluid balance.For desert rats and camels, the problem is conservation of water in an environment where standing water is nonexistent, temperature is high, and humidity is low. Despite these handicaps, desert rats are able to maintain the osmotic pressure of their blood, as well as their total body water content, at approximately the same levels as other rats. one countermeasure is behavioral：these rats stay in burrows during 'the hot part of the day, thus avoiding loss of fluid through panting or sweating, which are regulatory mechanisms for maintaining internal body temperature by evaporative cooling. Also, desert rats' kidneys can excrete a urine having twice as high a salt content as sea water.Camels, on the other hand, rely more on simple endurance. They cannot store water, and their reliance on an entirely unexceptional kidney results in a rate of water loss through renal function significantly higher than that of desert rats. As a result, camels must tolerate losses In Body water of up to thirty percent of their body weight. Nevertheless, camels do rely on a special mechanism to keep water loss within a tolerable range：by sweating and panting only when their body temperature exceeds that which would kill a human, they conserve internal water.Marine vertebrates experience difficulty with their water balance because though there is no shortage of seawater to drink, they must drink a lot of it to maintain their internal fluid balance. But the excess salts from the seawater must be discharged somehow, and the kidneys of most marine vertebrates are unable to excrete a urine in which the salts are more concentrated than in seawater. Most of these animals have special salt-secreting organs outside the kidney that enable them to eliminate excess salt.
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