Economists use two competing models to describe the effects of commercial advertising—advertising as market competition and advertising as market power. The market competition model holds that the fundamental function of advertising is lo provide information about products and brands. It is argued that information in ads permits greater marketplace efficiencies, such as lower prices and reduced monopoly power. In a similar vein, much discussion regarding political advertising has rested on its informational value. Does political advertising provide political information and help voters make informed decisions'1 Nelson argues that promoting bars of soap in commercial ads is no different than promoting political ideas ideology from political candidates in political ads. on the grounds that information is being distributed m both cases. Others, such as Ferguson and Jamieson, disagree with Nelson's proposition. Ferguson, for example, pointed out that choosing a political candidate is more like buying an experience good (where the quality is hard to evaluate prior to purchase) rather than a search good (where the quality is easily evaluated before the purchase). According to Ferguson, claims in political ads do not have true informational value, because it is difficult for voters to draw inferences about the future deeds of a candidate from what the ads say Furthermore. Jamieson argues that political ads reshape the public image of political candidates and change voters feelings about the candidates with subtle emotional cues but without substantive information upon which to base a reasoned judgment.
In the context of the passage as a whole, the highlighted sentence serves primarily to
Like paleontologists who interpret timescales from fossil evidence, we infer the history of star formation in the Milky Way galaxy from the heavy-element composition of its stars. According to the big bang theory of the origin of the universe, the first gas clouds—and the first generation of stars formed from them—were composed of pure hydrogen and helium; most heavier elements— iron and calcium, for example—came later, created by explosions of supernovas, massive stars in their death throes. Loaded with heavy elements, material ejected from supernovas enriched the interstellar gas clouds from which the next generation of stars formed, the level of heavy elements increasing with succeeding generations. Because most stars live for many billions of years and because the Milky Way is thus composed of multiple stellar generations, comparing the number of stars of low heavy-element abundance with those of high heavy-element abundance enables astronomers to untangle the history of star formation in the Milky Way.
The passage contains information about each of the following subjects EXCEPT the
Instances of "galactic cannibalism"—mergers in which large galaxies completely consume smaller ones—may be fairly common. Tidal forces produced by the Milky Way's powerful gravity, for example, appear to be dismantling and engulfing a dwarf galaxy in the constellation Sagittarius, producing large clumps and streamers of stars connecting the two galaxies. Astronomers have also observed two dense clusters of stars and gas at the heart of the Andromeda galaxy, an apparent "double nucleus" that may contain the remnant of a cannibalized dwarf galaxy. But this Twin-lobed appearance could also be created by two parts of a single nucleus bisected by a lane of dust. Scientists believe that only about 25 percent of such apparent double nuclei actually represent galactic cannibalism. Many of the rest result from the illusion of proximity that occurs when objects at different distances appear along the same line of sight: others consist of debris from galactic "collisions." in which one galaxy has passed through another without merging, causing waves of new star formation.
According to the passage, a true double nucleus may be produced by the
Scientists have long debated the exact timing of the lunar cataclysm, a period approximately 4 billion years ago when Earth and the Moon were pummeled with asteroids. A clue to this puzzle may come from spherules, millimeter-sized droplets of molten rock formed after an asteroid collides explosively with a planet. Upon impact, the asteroid vaporizes both itself and the target rock. producing a vapor plume that condenses into spherules. These form a layer preserved in rock, whose age can be estimated using radiometric dating. Scientists know of fourteen of these spherule layers scattered across Earth, but none dates to the theorized lunar cataclysm time period. Four layers, however, are from between 3.47 and 3.24 billion years ago. indicating perhaps a slow decline in collisions.
Which of the following might plausibly account for the findings in the highlighted sentence?
TESTED 23 Nov 2024
