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Ready4

A recent analysis has yielded information about the decline of megafauna (giant animals) in modern-day New Zealand. Evolutionary biologists compared DNA from fossils of nine species of moa, large flightless birds that lived for millions of years on the country's South Island. The birds' genetic information suggests that their populations were stable for at least 4,000 years before declining with extreme rapidity only after the arrival of humans on the New Zealand archipelago, 600 years ago.p> In reviewing possible causes for this phenomenon, the scientists dismissed the climatic explanation that accounts for the decline of other megafauna because the extinction happened long after other megafauna had disappeared at the end of the last Ice Age. They ruled out sampling bias because a sample selection impact would not have allowed for the different results observed between the nine species. They rejected the possibility of major impacts by disease or volcanic activity because consistent genetic diversity indicates that no population diminishment occurred prior to the arrival of humans to New Zealand. The lack of population decline prior to human arrival suggests that the moa extinction was caused entirely by human hunting—a hypothesis corroborated by the remains of moa at every life stage found in rubbish piles from the earliest decade of human occupation of the islands. Such evidence leads the researchers to believe that the earliest Polynesian arrivals to New Zealand engaged in indiscriminate hunting of moa and moa eggs because their large size made them attractive as easily obtained food.p>

C13

Despite views that globalization has reached its peak, a period beginning in the nineteenth century and extending into the early-twentieth century, in fact, is the interval during which international barriers to trade fell most steeply, as can be seen in the case of price convergence in commodities. The prices of cloves, pepper, and coffee failed to converge between Amsterdam and East Asia or between England and India from as far back as 1580 but began in 1820 to draw closer. Similarly, the difference in wheat prices in the United States and England fell from one hundred percent in the early-nineteenth century to negligible levels late in the century and to no difference at all in the early-twentieth century. A similar story unfolded during this period for bacon, cotton, and rice.p> Peter Lindert and Jeffrey Williamson have summarized the price gaps in commodity markets between continents as evolving in three phases. From 1820 to 1914, these gaps fell by 81 percent; they attribute 72 percent of this decline to cheaper transport and 28 percent to trade policies. Second, during the wartime period of 1914 to 1950, the gaps doubled, due to a reversal in trade policies. Finally, from 1950 to 2000, they fell again by 76 percent, ending up 92 percent lower than in 1820, with about four-fifths of the total change attributable to cheaper transport and one-fifth to more favorable trade policies.p> Trade data for this period are typically articulated in terms of ratio of total trade volume to gross domestic product, since commodity price information is not universally available. These ratios in many advanced economies were higher in the mid-1990s than in the early 1900s, but not by much. In Japan, notably, the percentage of GDP for which trade accounted in 1995 was 17 percent, far under its 1910 level of 30 percent, as measured in current prices. Sure enough, the ratios have risen somewhat in other economies over that same time period—by 13 percentage points in the United Kingdom, 8 points in France, and from 11 percent to 24 percent in the United States; this latter spike may explain why the attention to globalization has been especially acute in America. These increases, nevertheless, are modest given the fact that the world economy grew roughly twice as quickly in the twentieth century as in the nineteenth.p> The ratios above, and hence the substantiation for the argument that globalization peaked a century ago, grow much more dramatically if they are computed in constant prices rather than in current prices, because the prices of goods relative to services fell due to sustained increases in productivity in the sectors producing these goods. Trade has grown most in those sectors in which prices have most strikingly fallen, so the proportions of GDP in constant prices have risen more than those in current prices.p>

C13

In semi-aquatic ecosystems, bodies of water present peculiar difficulties for the hunting strategies of spiders. Ponds, lakes, and rivers can provide unnavigable escape vectors for prey organisms, making it likely that predators will lose out on valuable nutritional resources. The water spider Dolomedes, in particular, demonstrates adaptations that allow it to take advantage of waterborne food sources.p> The difficulty that members of the species Dolomedes face is best evidenced by the typical hunting strategies of terrestrial spiders. All spiders produce silk and arboreal species generally spin their silk into fine, latticework structures that they suspend in the environment to trap passing arthropods, which entangle themselves due to the exigencies of the forested ecosystem. In environs lacking tree coverage or comparable large structures, however, web-hunting becomes inefficient, and other strategies of predation have to be pursued. That many spider species persist in environments lacking significant tree coverage suggests that certain behavioral adaptations enable them to locate food effectively in a variety of environmental circumstances.p> One such adaptation is the proactive use of water bodies by Dolomedes, who eschew silk in favor of water tension, which they use to monitor the movements of prey animals. Organisms fall into a pond, lake, or river, and send waves vibrating from the point of impact across the surface of the pool. Dolomedes uses these vibrations to locate and capture the fallen organism. For arboreal spiders, who can only monitor the vibrations caused by insects caught in the webs they've spun, this is useless information. Such a hunting strategy does not require that the arboreal spiders pay attention to extraneous prey when other prey is acquired in abundance by other adaptations. In comparison, Dolomedes acquires its prey by yet another aquatic adaptation, using a coat of tiny, hydrophobic hairs that allow the spider to submerge itself in the liquid environment. By causing a pocket of air to gather and surround the surface of the spider's body, these hairs allow Dolomedes to submerge itself in water, thus giving it access to sources of prey closed off to other species.p>

Ready4

p> Each of the letters in the table above represents one of the numbers 3, 5, or 11, and each of these numbers occurs no more than once within any row or column, with the exception of 5, which may occur up to two times. What is the value of

d_{2}

?p>

$a_{1} c_{2} = 121$
$c_{1} d_{1} a_{2} e = 375$

Ready4

As the end of World War II brought about a housing boom, the market for consumer home lending expanded significantly, and the financial institutions that had traditionally provided mortgages to working-class Americans faced new competitive pressures. Although the United States League of Local Buildings and Loans in America (USLLBLA), an association of institutions focused on savings accounts and homeowner lending, did not oppose the entry of other lenders into the market, it did lobby to retain the privilege of offering higher interest rates on savings accounts than banks were allowed to give.p> These efforts were spurred in part by the expansion of the Federal Housing Administration (FHA), a federal agency that began to insure mortgages with increasingly consumer-friendly terms. The FHA rules, like USLLBLA, allowed people to afford homes who otherwise could not have done so. It did this in part by relaxing the regulations governing the maximum length of a mortgage and the minimum down payment required, making the loans available to those who accrued capital more slowly than the typical homeowner previously had. In response, the USLLBLA also formed the Voluntary Home Mortgage Credit Program (VHMCP), taking advantage of the new regulations to offer the more affordable loans to people in rural areas in hopes of forestalling further expansion of federal agencies into the mortgage business.p>

C13

A recent underwater survey has found clues in a Mayan cenote, a type of sinkhole, about the development of the Mesoamerican city of Mayapán (1150–1450 CE). The city wall curves to avoid this particular cenote, Sac Uayum, in which research divers found more than a dozen skeletal human remains. Normally cenotes are found within city limits, to provide water, so the location of the cenote and number of remains are notably atypical.p> Researchers are considering various possibilities to explain their findings. A theory that the cenote might have served as a general city cemetery was rejected, because most city residents were interred near or under their homes. A theory of ceremonial human sacrifice was dismissed because the bones were unmarked, showing no indications of rituals or cause of death. A theory of social elitism was eliminated, because shards of other artifacts discovered at the same site were mainly those of plain water pitchers, displaying no indications of wealth or high social rank. So far the most tenable interpretation under consideration is that the cenote may have served as an attempt at contagious-disease containment—a plague pit, kept deliberately beyond the city wall and apart from drinking water supplies. The persistence into modern times of local taboos and superstitions around Sac Uayum, threatening death if the gods are not appeased with rituals before the water is approached, lends further credence to the researchers' theory.p>

C13

Ready4

p>What is the circumference of the circle above with center $O$ ?p> p> (1) The perimeter of $\Delta OQS$ is $8+4\sqrt{2}$ .p> (2) The length of arc $QRS$ is $2\pi$ .p>

Ready4

If

r_{1}

and

r_{2}

are the roots of the equation

t^{2} + b t + c = 0

, where b and c are constants, are both

r_{1}

and

r_{2}

positive?p>

$b < 0$
$c < 0$

Ready4

The general theory of relativity posits that major events in the universe, such as the creation of a black hole, create ripples in the space-time continuum, also known as gravitational waves, which were recently detected for the first time by the Laser Interferometer Gravitational Observatory (LIGO). Though the interferometer was invented in 1887, not until 2002 was one used in an attempt to detect gravitational waves. The instrument splits a laser beam so that the two resulting beams travel down perpendicular arms—perfectly identical tubes that are four kilometers long—then hit mirrors and return to their shared origin point. This allows the instrument to detect extremely minute changes in the lengths of the arms. In the absence of a gravitational wave, the wavelengths of the two beams match up perfectly. However, if something interferes with the beams' paths, their peaks and valleys no longer align, and the instrument registers the interference.p> Gravitational waves cause space to shrink in one direction and expand in a perpendicular direction. If the interferometer is hit by a gravitational wave, one arm will grow and the other will shrink by normally imperceptible amounts, but the differing distances traveled by the laser beams are registered by the instrument. The LIGO actually consists of two interferometers, thousands of kilometers apart, which compare data in order to rule out localized vibrations and flickers. In September 2015 it detected its first gravitational wave, which was determined to have been generated by the collision of two black holes between one and two billion years ago. Another gravitational wave was detected in December 2015.p>

In the figure above, segments PQ and PR are each parallel to one of the rectangular coordinate axes. What is the sum of the coordinates of point P ?(1)The x - coordinate of point Q is -1.(2)The y - coordinate of point R is 1.

Ready4

m = \frac{\frac{3}{n}}{\frac{2}{y} + \frac{1}{2 y}}

In the expression above, if

y n \neq 0

, what is the value of m?p>

$y = \frac{3 n}{2}$
$n = \frac{3}{2}$

Ready4

The ages of all children in Group A are the same, and the ages of all children in Group B are the same. Is the age of a child in Group A less than the age of a child in Group B?p>

The sum of the ages of 3 children in Group A and 2 children in Group B is less than the sum of ages of 2 children in Group A and 4 children in Group B.
The sum of the ages of 4 children in Group A and 3 children in Group B is less than the sum of ages of 3 children in Group A and 4 children in Group B.

All figures are in millions (M) except for EPS which is in $/share. EPS stands for Earnings Per Share. Market Capitalization is defined as stock price (measured in $/share) multiplied by shares outstanding."Earnings" when used in the expression EPS (earnings per share) and P/E (price-to-earnings ratio) refer to the metric net income (not shown).Capitalization metrics such as market capitalization value and enterprise value are as of January 30, 2008. Other metrics are as of December 2007.EBITDA is a financial metric for profitability and is defined as earnings before interest, taxes, depreciation, and amortization. GMAT、gmat题库、gmat模考、gmat考满分

For each of the following, select Yes if the statement is true based on the information provided; otherwise select No.

C13

As understandings of the solar life cycle developed, scientists were confronted by a nagging question: If, early in the history of Earth's planetary formation, the sun was significantly dimmer than it is now, how do we explain evidence for the presence of liquid water on the planet's surface during this period? It is understood that during the early Earth period our sun would have shone at about 70 percent of its current luminosity, significantly below the level necessary to sustain the presence of liquid oceans on the planet's surface. But paleontological and geological records indicate with substantial certainty that liquid water was present on the Earth's surface during this time. If scientific models of solar development and the early geological history of Earth are to be reconciled, there must have been some other, intervening factor affecting surface temperatures during this early period of geologic history.p> Our method of reconciling these two apparently contradictory bodies of evidence has been to analyze the characteristics and chemical composition of Earth's atmosphere during its various periods of geological development. We have known for decades that the presence of certain vapors in the air, commonly known as “greenhouse gases,” increases the amounts of heat retained by an atmosphere to a degree proportionate to the concentration of greenhouse gases within it. If the Earth was warmer in the past than solar luminosity would suggest—and we have strong evidence that it was—then we can expect that the distribution of greenhouse gases in its atmosphere would be of paramount value in explaining that discrepancy. Heightened greenhouse gas levels would trap and magnify the sun's heat as it struck the atmosphere, enabling liquid water to exist on the surface of Earth. However, we have discovered little evidence that greenhouse gases during the early Earth period were present in larger quantities than previously assumed. These surprising findings indicate that the discrepancy between solar-astronomical and geological evidence related to the development of Earth's oceans cannot be explained by the presence of carbon in the atmosphere.p> One likely alternative is that another, non-solar source for atmospheric heat during the early Earth period. Earth and its moon were much closer together in the early geologic history of the planet, and tidal heating caused by the moon's rotation around Earth was likely much greater. While it is unclear how much influence this phenomenon might have exerted over atmospheric temperatures, scientists are increasingly convinced that it could play a part in explaining the unlikely presence of liquid water on our infant planet, perhaps in combination with indeterminate geological activity, solar flares, or irregularities in Earth's magnetic field.p>

Ready4

Box	$B1$	$B2$	$B3$	$B4$	$B5$	$B6$
Fraction of the Total Value of Rachel's Order	$\frac{1}{4}$	$\frac{5}{24}$	$\frac{3}{16}$	$\frac{1}{6}$	$\frac{1}{8}$	$\frac{1}{16}$

Rachel submitted an order for several items from a popular online retail site. Her items were packaged in 6 separate boxes and were delivered on Monday and Tuesday of this past week. Each box was labeled $B1$ , $B2$ , $B3$ , $B4$ , $B5$ , or $B6$ . The table shows the value of each box as a fraction of the total value of Rachel's order. If the delivery on Monday had a value greater than $\frac{1}{2}$ of the total value of Rachel's order, was box $B4$ delivered on Monday?p> (1) $B3$ and $B5$ were delivered on Monday.p> (2) $B1$ and $B2$ were delivered on Tuesday.p>

Ready4

Short Story	$S1$	$S2$	$S3$	$S4$	$S5$	$S6$
Fraction of the Total Reading Assignment	$\frac{1}{3}$	$\frac{1}{4}$	$\frac{1}{6}$	$\frac{1}{9}$	$\frac{1}{12}$	$\frac{1}{18}$