MCAT Section 3: Physical Sciences (Full version) SECTION 3: PHYSICAL SCIENCES Exam Questions in PDF

Muzak, the intentionally unobtrusive music that most people associate with elevators and dentists' waiting rooms, represents the paradoxical success story of a product designed to be ignored. Although few people admit to enjoying its blandly melodic sounds, Muzak reaches over 100 million listeners in 14 countries and has played in the White House, the Apollo lunar spacecraft, and countless supermarkets, offices, and factories. This odd combination of criticism and widespread acceptance is not surprising, however, when one considers that Muzak is not created for the enjoyment of its listeners: rather, its purpose is to modify physiological and psychological aspects of an environment.
In the workplace, Muzak is credited with increasing both productivity and profitability. Research into the relationship between music and productivity can be traced to the earliest days of the Muzak Corporation. Developed by a military officer in 1922 as a way of transmitting music through electrical wires, Muzak blossomed in the 1930's following a study which reported that people work harder when they listen to certain kinds of music. Impressed by these findings, the BBC began to broadcast music in English munitions factories during World War II in an effort to combat fatigue. When workers assembling weapons increased their output by 6 percent, the U.S. War Production Board contracted the Muzak Corporation to provide uplifting music to American factories. Today, the corporation broadcasts its "Environmental Music" to countless businesses and institutions throughout the world. And while most people claim to dislike Muzak's discreet cadences, it seems to positively influence both productivity and job satisfaction.
Researchers speculate that listening to Muzak and other soft music improves morale and reduces stress by modifying our physiology. Physiological changes such as lowered heart rate and decreased blood pressure have been documented in hospital studies testing the effect of calming music on cardiac patients. In addition, certain kinds of music seem to effect one's sense of emotional, as well as physical, well being. It is just this sort of satisfaction which is thought to result in increased performance in the workplace. In a study of people performing repetitive clerical tasks, those who listened to music performed more accurately and quickly than those who worked in silence; those who listened to Muzak did better still. Moreover, while Muzak was conceived as a tool for productivity, it also seems to influence a business' profitability. In an experiment in which supermarket shoppers shopped to the mellow sounds of Muzak, sales were increased by as much as 12 percent.
What makes Muzak unique is a formula by which familiar tunes are modified and programmed. Careful instrumentation adds to an overall sound that is neither monotonous nor rousing. But it is the precisely timed programming that separates Muzak from other "easy listening" formats. At the core of the programming is the concept of the "Stimulus Progression". Muzak programs are divided into quarter-hour groupings of songs, and are specifically planned for the time of day at which they will be heard. Each composition is assigned a mood rating between 1 and 6 called a stimulus value; a song with a rating of 2, for example, is slower and less invigorating than one with a value of 5. Approximately six compositions with ascending stimulus values play during any given quarter hour; each 15-minute segment ends in silence. Each segment of a 24-hour program is carefully planned. Segments that are considered more stimulating air at 11 a.m. and 3 p.m. (the times when workers typically tire), while more soothing segments play just after lunchtime and towards the end of the day, when workers are likely to be restless.
From the point of view of management, then, Muzak is a useful tool in the effort to maximize both productivity and profits. However, some people object to its presence, labeling it as a type of unregulated air pollution. Still others see it as an Orwellian nightmare, a manipulation of the subconscious. But Muzak's effectiveness seems to lie in the fact that most people never really listen to it. While it may be true that no one actually likes this carefully crafted aural atmosphere, many simply ignore it, allowing its forgettable sounds to soften the contours of the day.
It can be inferred from the statements in the passage that the author regards Muzak as:

The Russian wheat aphid, Diuraphis noxia, is a small green insect discovered in southern Russia around the turn of the century. Agricultural researchers are not quite sure, but they believe the Russian aphid adapted itself to wheat about ten thousand years ago, when the crop was first domesticated by man. What is not in doubt is the insect's destructiveness. Spread by both wind and human transport, the Russian aphid has destroyed wheat fields throughout Asia, Africa, and Latin America. Until a few years ago, the United States had been free of this pest. But in the spring of 1986, a swarm of Russian aphids crossed the Mexican border and settled a few hundred miles north, in central Texas. From there, it quickly spread to other Western states, destroying wheat fields all along its path. In fact, the level of destruction has been so great over the past five years that entomologists are calling the Russian aphid the greatest threat to American agriculture since the Hessian fly, Phytophaga destructor, was inadvertently brought to the colonies on ships by German mercenary troops during the Revolutionary War. A combination of several factors have made it particularly difficult to deal with the threat posed by this aphid. First, Russian aphids reproduce asexually at a phenomenal rate. This process, known as parthenogenesis, often results in as many as twenty generations of insects in a single year. Although most generations remain in a limited geographic area because they have no wings, a few generations are born with wings, allowing the insect to spread to new areas. Second, because wheat is a crop with a very low profit margin, most American farmers do not spray it with pesticides; it simply is not economical to do so. And since the Russian aphid has only recently entered the United States, it has no natural enemies among North American insects or animals. As a result, there have been no man-made or natural obstacles to the spread of the Russian aphid in the United States.
Agricultural researchers seeking to control the Russian aphid have looked to its place of origin for answers. In the Soviet Union, the Russian aphid has been kept in check by predators which have evolved alongside it over many thousands of years. One species of wasp seems to be particularly efficient at destroying the aphid. The pregnant females of the species search the Russian aphid's home, the interior of a wheat stalk, sting the aphid into paralysis, and then inject an egg into its body. When the egg hatches the wasp larva feeds off of the aphid, killing it in the process.
The introduction of predators like the wasp, coupled with the breeding of new strains of insect-resistant wheat, may substantially curb the destructiveness of the Russian aphid in the future. For the time being, however, American farmers are left to their own devices when it comes to protecting their wheat crops.
Which of the following statements would be most in agreement with the statements in the passage?

The Russian wheat aphid, Diuraphis noxia, is a small green insect discovered in southern Russia around the turn of the century. Agricultural researchers are not quite sure, but they believe the Russian aphid adapted itself to wheat about ten thousand years ago, when the crop was first domesticated by man. What is not in doubt is the insect's destructiveness. Spread by both wind and human transport, the Russian aphid has destroyed wheat fields throughout Asia, Africa, and Latin America. Until a few years ago, the United States had been free of this pest. But in the spring of 1986, a swarm of Russian aphids crossed the Mexican border and settled a few hundred miles north, in central Texas. From there, it quickly spread to other Western states, destroying wheat fields all along its path. In fact, the level of destruction has been so great over the past five years that entomologists are calling the Russian aphid the greatest threat to American agriculture since the Hessian fly, Phytophaga destructor, was inadvertently brought to the colonies on ships by German mercenary troops during the Revolutionary War. A combination of several factors has made it particularly difficult to deal with the threat posed by this aphid. First, Russian aphids reproduce asexually at a phenomenal rate. This process, known as parthenogenesis, often results in as many as twenty generations of insects in a single year. Although most generations remain in a limited geographic area because they have no wings, a few generations are born with wings, allowing the insect to spread to new areas. Second, because wheat is a crop with a very low profit margin, most American farmers do not spray it with pesticides; it simply is not economical to do so. And since the Russian aphid has only recently entered the United States, it has no natural enemies among North American insects or animals. As a result, there have been no man-made or natural obstacles to the spread of the Russian aphid in the United States.
Agricultural researchers seeking to control the Russian aphid have looked to its place of origin for answers. In

the Soviet Union, the Russian aphid has been kept in check by predators which have evolved alongside it over many thousands of years. One species of wasp seems to be particularly efficient at destroying the aphid. The pregnant females of the species search the Russian aphid's home, the interior of a wheat stalk, sting the aphid into paralysis, and then inject an egg into its body. When the egg hatches the wasp larva feeds off of the aphid, killing it in the process.
The introduction of predators like the wasp, coupled with the breeding of new strains of insect-resistant wheat, may substantially curb the destructiveness of the Russian aphid in the future. For the time being, however, American farmers are left to their own devices when it comes to protecting their wheat crops.
According to the passage, which of the following statements is/are true of Russian wheat aphids?
I). Most are capable of flight.
II). They are resistant to pesticides.
III). They are capable of spreading rapidly.

The Russian wheat aphid, Diuraphis noxia, is a small green insect discovered in southern Russia around the turn of the century. Agricultural researchers are not quite sure, but they believe the Russian aphid adapted itself to wheat about ten thousand years ago, when the crop was first domesticated by man. What is not in doubt is the insect's destructiveness. Spread by both wind and human transport, the Russian aphid has destroyed wheat fields throughout Asia, Africa, and Latin America. Until a few years ago, the United States had been free of this pest. But in the spring of 1986, a swarm of Russian aphids crossed the Mexican border and settled a few hundred miles north, in central Texas. From there, it quickly spread to other Western states, destroying wheat fields all along its path. In fact, the level of destruction has been so great over the past five years that entomologists are calling the Russian aphid the greatest threat to American agriculture since the Hessian fly, Phytophaga destructor, was inadvertently brought to the colonies on ships by German mercenary troops during the Revolutionary War. A combination of several factors has made it particularly difficult to deal with the threat posed by this aphid. First, Russian aphids reproduce asexually at a phenomenal rate. This process, known as parthenogenesis, often results in as many as twenty generations of insects in a single year. Although most generations remain in a limited geographic area because they have no wings, a few generations are born with wings, allowing the insect to spread to new areas. Second, because wheat is a crop with a very low profit margin, most American farmers do not spray it with pesticides; it simply is not economical to do so. And since the Russian aphid has only recently entered the United States, it has no natural enemies among North American insects or animals. As a result, there have been no man-made or natural obstacles to the spread of the Russian aphid in the United States.
Agricultural researchers seeking to control the Russian aphid have looked to its place of origin for answers. In the Soviet Union, the Russian aphid has been kept in check by predators which have evolved alongside it over many thousands of years. One species of wasp seems to be particularly efficient at destroying the aphid. The pregnant females of the species search the Russian aphid's home, the interior of a wheat stalk, sting the aphid into paralysis, and then inject an egg into its body. When the egg hatches the wasp larva feeds off of the aphid, killing it in the process.
The introduction of predators like the wasp, coupled with the breeding of new strains of insect-resistant wheat, may substantially curb the destructiveness of the Russian aphid in the future. For the time being, however, American farmers are left to their own devices when it comes to protecting their wheat crops.
It can reasonably be inferred that the author of the passage is:

The Russian wheat aphid, Diuraphis noxia, is a small green insect discovered in southern Russia around the turn of the century. Agricultural researchers are not quite sure, but they believe the Russian aphid adapted itself to wheat about ten thousand years ago, when the crop was first domesticated by man. What is not in doubt is the insect's destructiveness. Spread by both wind and human transport, the Russian aphid has destroyed wheat fields throughout Asia, Africa, and Latin America. Until a few years ago, the United States had been free of this pest. But in the spring of 1986, a swarm of Russian aphids crossed the Mexican border and settled a few hundred miles north, in central Texas. From there, it quickly spread to other Western states, destroying wheat fields all along its path. In fact, the level of destruction has been so great over the past five years that entomologists are calling the Russian aphid the greatest threat to American agriculture since the Hessian fly, Phytophaga destructor, was inadvertently brought to the colonies on ships by German mercenary troops during the Revolutionary War. A combination of several factors has made it particularly difficult to deal with the threat posed by this aphid. First, Russian aphids reproduce asexually at a phenomenal rate. This process, known as parthenogenesis, often results in as many as twenty generations of insects in a single year. Although most generations remain in a limited geographic area because they have no wings, a few generations are born with wings, allowing the insect to spread to new areas. Second, because wheat is a crop with a very low profit margin, most American farmers do not spray it with pesticides; it simply is not economical to do so. And since the Russian aphid has only recently entered the United States, it has no natural enemies among North American insects or animals. As a result, there have been no man-made or natural obstacles to the spread of the Russian aphid in the United States.
Agricultural researchers seeking to control the Russian aphid have looked to its place of origin for answers. In the Soviet Union, the Russian aphid has been kept in check by predators which have evolved alongside it over many thousands of years. One species of wasp seems to be particularly efficient at destroying the aphid. The pregnant females of the species search the Russian aphid's home, the interior of a wheat stalk, sting the aphid into paralysis, and then inject an egg into its body. When the egg hatches the wasp larva feeds off of the aphid, killing it in the process.
The introduction of predators like the wasp, coupled with the breeding of new strains of insect-resistant wheat, may substantially curb the destructiveness of the Russian aphid in the future. For the time being, however, American farmers are left to their own devices when it comes to protecting their wheat crops.
The passage supplies information for answering all of the following questions EXCEPT: