Nokea
Water is needed to sustain practically all life functions on planet Earth. A single drop of this compound is composed of an oxygen atom that shares its electrons with each of the two hydrogen atoms. The cycle starts when precipitation, such as rain, snow, sleet, or hail, descends from the sky onto the ground. Water that is not absorbed immediately from the precipitation is known as runoff. The runoff flows across the land and collects in groundwater reservoirs, rivers, streams, and oceans.Evaporation takes place when liquid water changes into water vapor, which is a gas. Water vapor returns to the air from surface water and plants.Ultimately, condensation happens when this water vapor cools and changes back into droplets of liquid. In fact, the puffy, cotton clouds that we observe are formed by condensation. When the clouds become heavily laden with liquid droplets, precipitation ensues.
What is the meaning of the word 'composed' in the first paragraph?
- A. To consist of
- B. To be uniquely discovered
- C. To be set apart
- D. To be surprised
Correct Answer: A
Rationale: In the context provided, 'composed' means to consist of. The paragraph explains that a drop of water is composed of an oxygen atom and two hydrogen atoms. Therefore, the correct answer is A. Choice B, 'To be uniquely discovered,' is incorrect as it does not relate to the composition of a drop of water. Choice C, 'To be set apart,' and Choice D, 'To be surprised,' are also incorrect as they do not convey the meaning of 'composed' as it is used in this paragraph.
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Water is needed to sustain practically all life functions on planet Earth. A single drop of this compound is composed of an oxygen atom that shares its electrons with each of the two hydrogen atoms. The cycle starts when precipitation, such as rain, snow, sleet, or hail, descends from the sky onto the ground. Water that is not absorbed immediately from the precipitation is known as runoff. The runoff flows across the land and collects in groundwater reservoirs, rivers, streams, and oceans.Evaporation takes place when liquid water changes into water vapor, which is a gas. Water vapor returns to the air from surface water and plants.Ultimately, condensation happens when this water vapor cools and changes back into droplets of liquid. In fact, the puffy, cotton clouds that we observe are formed by condensation. When the clouds become heavily laden with liquid droplets, precipitation ensues.
What was the author's primary purpose for writing this essay?
- A. To persuade the reader to conserve water
- B. To persuade the reader that runoff is not the best way to collect water
- C. To analyze different types of runoff
- D. To inform the reader about the stages of the water cycle
Correct Answer: D
Rationale: The correct answer is D. The author's primary purpose for writing the essay is to inform the reader about the stages of the water cycle. The essay discusses the various stages of the water cycle, including precipitation, runoff, evaporation, and condensation. Choices A, B, and C are incorrect because the essay focuses on explaining the water cycle stages rather than persuading the reader to conserve water, discussing the effectiveness of runoff, or analyzing different types of runoff.
Foodborne illnesses are contracted by eating food or drinking beverages contaminated with bacteria, parasites, or viruses. Harmful chemicals can also cause foodborne illnesses if they have contaminated food during harvesting or processing. Foodborne illnesses can cause symptoms ranging from upset stomach to diarrhea, fever, vomiting, abdominal cramps, and dehydration. Most foodborne infections are undiagnosed and unreported, though the Centers for Disease Control and Prevention estimates that every year about 76 million people in the United States become ill from pathogens in food. About 5,000 of these people die.Harmful bacteria are the most common cause of foodborne illness. Some bacteria may be present at the point of purchase. Raw foods are the most common source of foodborne illnesses because they are not sterile; examples include raw meat and poultry contaminated during slaughter. Seafood may become contaminated during harvest or processing. One in 10,000 eggs may be contaminated with Salmonella inside the shell. Produce, such as spinach, lettuce, tomatoes, sprouts, and melons, can become contaminated with Salmonella, Shigella, or Escherichia coli (E. coli). Contamination can occur during growing, harvesting, processing, storing, shipping, or final preparation. Sources of produce contamination vary, as these foods are grown in soil and can become contaminated during growth, processing, or distribution. Contamination may also occur during food preparation in a restaurant or a home kitchen. The most common form of contamination from handled foods is the calicivirus, also called the Norwalk-like virus.When food is cooked and left out for more than two hours at room temperature, bacteria can multiply quickly. Most bacteria don't produce an odor or change in color or texture, so they can be impossible to detect. Freezing food slows or stops bacteria's growth, but does not destroy the bacteria. The microbes can become reactivated when the food is thawed. Refrigeration also can slow the growth of some bacteria. Thorough cooking is required to destroy the bacteria.
What is the meaning of the word 'pathogens' as it is used in the first paragraph?
- A. diseases
- B. vaccines
- C. disease-causing substances
- D. foods
Correct Answer: C
Rationale: In the context provided, 'pathogens' refers to disease-causing substances such as bacteria and viruses. These microorganisms can contaminate food and lead to foodborne illnesses. Choice A ('diseases') is incorrect as pathogens themselves cause diseases but are not diseases. Choice B ('vaccines') is incorrect as vaccines are used to prevent diseases caused by pathogens. Choice D ('foods') is incorrect as pathogens are not foods, but rather contaminants that can be found in food.
Beep!…Beep!…Beep! is the audible rhythmic sound made as the strength of the heart muscle is measured. The signal cadence has a characteristic record that varies in every individual. This record is called an electrocardiogram, or ECG.
In the body, an array of systemic neural responses constantly occur, emitting electric currents. The electric currents can be detected on the surface of the body, and if a person is hooked to an amplifier, these impulses are recorded by an electrocardiograph. Most of the information obtained is about the heart because the heart sends out electric currents in waves. This “wave of excitation†spreads through the heart wall and is accompanied by electric changes.
The wave takes place in three distinct steps. Initially, the “wave of excitation†accompanied by an electric change lasts for approximately 1 to 2 seconds after the contraction of the cardiac muscle. The electric impulses are discharged rhythmically from the sinoatrial (SA) node, the pacemaker of the heart. This spread of excitation over the muscle of the atrium indicates that the atrium has contracted. Next, the peak of the ECG reading is due to the atrioventricular (AV) node, causing the ventricle to become excited. Finally, the ventricles relax, and any changes in the wave indicate to trained medical staff any abnormalities within the heart.
What is the author's primary purpose in writing the essay?
- A. To persuade the reader to have an ECG
- B. To entertain the reader with a heartwarming story
- C. To inform the reader how an electrocardiograph reads the electric currents emitted by the heart
- D. To analyze the difference between the SA node and the AV node
Correct Answer: C
Rationale: The author's primary purpose in writing the essay is to inform the reader about how an electrocardiograph reads the electric currents emitted by the heart. Choice A is incorrect because there is no attempt to persuade the reader to have an ECG. Choice B is incorrect because the essay is focused on providing information rather than entertaining with a heartwarming story. Choice D is incorrect as the essay does not primarily analyze the difference between the SA node and the AV node; instead, it focuses on explaining how an electrocardiograph reads electric currents from the heart.
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 ambulance'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.
Which sound waves have a lower pitch?
- A. Those waves that are closer together
- B. Those waves that are farther apart
- C. Those waves that travel a long distance
- D. Those waves that travel a short distance
Correct Answer: B
Rationale: Sound waves that are farther apart have a lower pitch. The Doppler Effect explains that as objects emitting sound move away, the sound waves become more spaced out, resulting in a lower frequency and a lower pitch. Choice A is incorrect because waves that are closer together have a higher frequency and a higher pitch. Choices C and D are not directly related to determining the pitch of sound waves.
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 body's cardiovascular system. The body'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 body's blood pressure regulated. Three of the basic components are baroreceptors, chemoreceptors, and the kidneys.<p>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 send impulses from the arteries, while the kidneys 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: The correct answer is A. Baroreceptors and chemoreceptors send impulses from the arteries, while the kidneys control blood volume. Baroreceptors and chemoreceptors are responsible for monitoring blood pressure by sensing changes in pressure, oxygen levels, carbon dioxide levels, and pH within the arteries. They send out impulses to raise or lower blood pressure accordingly. On the other hand, the kidneys play a crucial role in regulating blood volume by absorbing salts and water and removing waste products. This key difference highlights that while baroreceptors and chemoreceptors are involved in monitoring and regulating blood pressure, the kidneys primarily focus on controlling blood volume. Choice B is incorrect because it inaccurately states that baroreceptors and chemoreceptors help maintain blood volume, which is not their primary function. Choice C is incorrect as it provides an inaccurate comparison between the roles of baroreceptors, chemoreceptors, and the kidneys. Choice D is incorrect as it wrongly associates the location of baroreceptors and chemoreceptors with the adrenal cortex, which is not accurate.