Nokea
Have you ever wondered why the whistle of a traveling, distant locomotive predicts its approach several yards before anyone actually sees it? Or why an oncoming ambulanceĆ¢Ä‚¬Ä„¢s screaming siren is heard momentarily several feet before the ambulance comes into full view, before it passes you, and why its siren is still heard faintly well after the ambulance is out of sight?
What you are witnessing is a scientific phenomenon known as the Doppler Effect. What takes place is truly remarkable. In both of these instances, when the train or ambulance moves toward the sound waves in front of it, the sound waves are pulled closer together and have a higher frequency. In either instance, the listener positioned in front of the moving object hears a higher pitch. The ambulance and locomotive are progressively moving away from the sound waves behind them, causing the waves to be farther apart and to have a lower frequency. These fast-approaching modes of transportation distance themselves past the listener, who hears a lower pitch.
What is the main idea of the passage?
- A. Trains and ambulances emit distinctively loud noises.
- B. Low-frequency waves produce high-pitched sounds.
- C. High-frequency waves result in low-pitched sounds.
- D. The Doppler Effect explains why sound is heard more strongly initially and then faintly after a moving object has passed.
Correct Answer: D
Rationale: The main idea of the passage is to explain the phenomena of the Doppler Effect in relation to the sound produced by moving objects like trains and ambulances. The Doppler Effect causes sound waves to be compressed and have a higher frequency as the object approaches, resulting in a higher pitch. Conversely, as the object moves away, the sound waves are stretched, leading to a lower frequency and a lower pitch. This effect clarifies why the sound is heard more loudly when the object is approaching, and then faintly when it has passed. Therefore, choice D is the correct answer as it summarizes the key concept discussed in the passage.
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Nurseries: If you thought nurseries were just for babies, well, think again! Being special kinds of farms, nurseries are used to raise plants in mass quantities. Plants, trees, and shrubs are typically grown in nurseries and then sold to farmers and gardeners to plant in homes, businesses, and farms. Most nurseries are found in the more rural parts of the country because much land is required to have a viable nursery. If a nursery sells plants to others, it must obtain a special permit from the local city or county, which keeps the competition fair and does not saturate the market with a large number of nurseries selling similar products.
Also on the grounds of nurseries are greenhouses which are made of glass or plastic panes that protect the plants from weather elements that may harm them and cause them not to grow and develop. The glass panels in greenhouses allow for sunlight to enter and moisture to be trapped inside. This creates a tropical environment which allows orchids and poinsettias to grow. It ensures that vegetables and fruits will grow large, which makes them valuable to farmers.
Why does a nursery that sells plants need a special permit?
- A. Operating in bad weather requires a special permit.
- B. The nursery owners need to be controlled.
- C. Too many nurseries mean not enough buyers for the plants that need to be sold.
- D. It is illegal to have nurseries in some states.
Correct Answer: C
Rationale: The correct answer is C: Too many nurseries mean not enough buyers for the plants that need to be sold. This is because if there are too many nurseries selling similar products in a specific area, it can lead to oversaturation of the market, resulting in a surplus of plants and not enough demand from buyers. This can negatively impact the sales and profitability of the nurseries.
Rationale:
1. Operating in bad weather requires a special permit (Choice A) is incorrect because the need for a special permit is not related to weather conditions.
2. The nursery owners need to be controlled (Choice B) is incorrect because the special permit is not about controlling the owners but rather about regulating the number of nurseries to maintain market balance.
3. It is illegal to have nurseries in some states (Choice D) is incorrect because the passage does not mention any legal restrictions on having nurseries; the need for a special permit is more about market regulation.
Food
Food and drink are necessary and desirable, but their abuse can cause serious physical and mental problems. Many physicians believe that overeating is one of the countryÄ€™s main health problems, since It places a great strain on the heart, can lead to diabetes, and often shortens the individual's life span. To fill an emotional void, people often turn to food when they are bored or lonely.
Another area of concern is alcohol consumption. The results of alcohol abuse are widely publicized. The social drinker who becomes alcoholic, the drunken drivers contribution to highway deaths, spousal and child abuse, are all concomitant problems associated with alcohol abuse.
As used in the last sentence of this paragraph, the term 'concomitant' means
- A. quiet
- B. unpredictable
- C. separate
- D. accompanying
Correct Answer: D
Rationale: The term 'concomitant' refers to something that accompanies or occurs alongside something else. In the context of the sentence, it describes the problems associated with alcohol abuse that occur together with issues such as drunken driving and spousal or child abuse. Therefore, the correct answer is D, meaning 'accompanying.'
Blood Pressure Regulators
The body is composed of systems that have evolved and diversified in order to maintain the natural functions and processes they regulate. One such system that has these regulators is the bodyÄ€™s cardiovascular system. The bodyÄ€™s pump, which regulates the flow of vitally needed oxygen to all cells of the body, as well as the discard of carbon dioxide and other waste products, is the heart.
Because blood pressure varies at different points within the body, differing components are needed to keep the bodyÄ€™s blood pressure regulated. Three of the basic components are baroreceptors, chemoreceptors, and the kidneys.
Baroreceptors are stretch receptors composed of fine branching nerve endings and are contained along the walls of the arteries near the heart and in other areas of the body as well. Impulses are related to this stretching along the arterial walls, which causes these baroreceptors to send out even more impulses to the heart, arteries, and veins, causing the blood pressure to go either up or down.
Chemoreceptors are located along the walls of the arteries and monitor changes in oxygen level, carbon dioxide, and pH. Just think! A fall in oxygen causes receptors to send impulses to raise the blood pressure.
The kidneys play a role in regulating blood pressure by absorbing salts and water and removing wastes. Hormones secreted by the adrenal cortex cause the kidney to keep or let go of any salt and water. This has an influence on blood volume and consequently on blood pressure.
What is a major difference in the way baroreceptors and chemoreceptors work from the way the kidneys work?
- A. Baroreceptors and chemoreceptors both work within the wall of the arteries, sending out impulses to raise or lower blood pressure, whereas the kidneys help control blood volume.
- B. Baroreceptors and chemoreceptors both work to help maintain blood volume, whereas the kidneys take care of salts, water, and waste removal.
- C. Baroreceptors and chemoreceptors must work together to control blood pressure, whereas the kidneys work with the adrenal cortex.
- D. Baroreceptors and chemoreceptors are both located near the adrenal cortex, whereas the kidneys are located near the heart.
Correct Answer: A
Rationale: Baroreceptors and chemoreceptors function by sensing changes in the body's blood pressure within the walls of the arteries and sending signals to raise or lower blood pressure accordingly. On the other hand, the kidneys play a role in controlling blood volume by absorbing salts and water and removing wastes. This contrast highlights a major difference between how baroreceptors/chemoreceptors regulate blood pressure and how the kidneys manage blood volume. While the former adjust blood pressure directly, the kidneys affect blood volume, which indirectly influences blood pressure. Therefore, option A correctly distinguishes the roles of baroreceptors/chemoreceptors and kidneys in maintaining cardiovascular homeostasis.
The immune system is a network of cells, tissues, and organs that defends the body against attacks by foreign invaders. These invaders are primarily microbes—tiny organisms such as bacteria, parasites, and fungi—that can cause infections. Viruses also cause infections, but are too primitive to be classified as living organisms. The human body provides an ideal environment for many microbes. It is the immune system’s job to keep the microbes out or destroy them. The immune system is amazingly complex. It can recognize and remember millions of different enemies, and it can secrete fluids and cells to wipe out nearly all of them. The secret to its success is an elaborate and dynamic communications network. Millions of cells, organized into sets and subsets, gather and transfer information in response to an infection. Once immune cells receive the alarm, they produce powerful chemicals that help to regulate their own growth and behavior, enlist other immune cells, and direct the new recruits to trouble spots. Although scientists have learned much about the immune system, they continue to puzzle over how the body destroys invading microbes, infected cells, and tumors without harming healthy tissues. New technologies for identifying individual immune cells are now allowing scientists to determine quickly which targets are triggering an immune response. Improvements in microscopy are permitting the first-ever observations of living B cells, T cells, and other cells as they interact within lymph nodes and other body tissues. In addition, scientists are rapidly unraveling the genetic blueprints that direct the human immune response, as well as those that dictate the biology of bacteria, viruses, and parasites. The combination of new technology with expanded genetic information will no doubt reveal even more about how the body protects itself from disease.
What is the meaning of the word 'ideal' as it is used in the first paragraph?
- A. thoughtful
- B. confined
- C. hostile
- D. perfect
Correct Answer: D
Rationale: In the context of the first paragraph, the word 'ideal' is used to describe the human body as a perfect or optimal environment for many microbes. It means that the human body provides a setting that is best suited or most favorable for the growth and survival of these microbes. Therefore, the correct answer is 'D: perfect.' The word 'thoughtful' (choice A) does not align with the context of the paragraph, 'confined' (choice B) suggests restricted rather than favorable, and 'hostile' (choice C) is the opposite of what is described in the text.
Not only the students but also the professor___ stunned by the test results.
- A. Was
- B. Were
- C. Are
- D. Be
Correct Answer: A
Rationale: The correct answer is 'A: Was.' In this sentence, 'Not only the students but also the professor' is a compound subject. When there are two subjects joined by 'not only...but also,' the verb agrees with the subject closest to it. In this case, 'professor' is singular, so the correct verb form is 'was.' Therefore, the sentence should read, 'Not only the students but also the professor was stunned by the test results.'