Nokea
Blood Pressure
Lub-dub! Lub-dub! Lub-dub! This sound is made by the rapid contracting and extending of the chamber doors on the inside of the heart. This ventricular contracting injects roughly 70 mL of blood into a vascular system with a given volume at differing pressure. Blood pressure refers to the pressure in the arterial system; and it is typically taken in the brachial artery of the arm because the pressure at different places along the circulatory route is different. Blood pressure is simply the force that the blood exerts in all directions within any given area and is the basis for the movement of blood from the heart, through the body, and back to the heart. This pressure is commonly expressed as a ratio of the systolic pressure over the diastolic pressure. The systolic pressure or “high peak†pressure takes place within the arterial system as ventricles contract and force blood into the arteries. The diastolic pressure or “low peak†pressure takes place within this arterial system just before the next ventricular contraction. An increase in blood pressure can occur if the arterial walls lose some of their elasticity with age or disease.
Which is the best summary of this passage?
- A. The heart pumps roughly 70 mL of blood by rapidly contracting and extending the chamber doors of the heart. Disease and age affect the pressure of blood on arterial walls.
- B. The brachial artery of the arm is usually used to take blood pressure, although the pressure is different in different parts of the body.
- C. The measurement of the ratio of systolic pressure over the diastolic pressure is known as blood pressure.
- D. The force that blood exerts on arterial walls is known as blood pressure and is measured as a ratio of the systolic pressure or "high peak" over the diastolic pressure or "low peak"
Correct Answer: D
Rationale: The correct summary of the passage is that blood pressure is the force exerted by blood on arterial walls, measured as a ratio of systolic pressure over diastolic pressure. This summary encapsulates the key points discussed in the passage, including the definition of blood pressure, its measurement, and the role of systolic and diastolic pressures. The other options either focus on specific details or do not encompass the main concept of blood pressure as explained in the passage.
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The immune system is a network of cells, tissues, and organs that defends the body against attacks by foreign invaders. These invaders are primarily microbesĆ¢Ä‚¬Ä€¯tiny organisms such as bacteria, parasites, and fungiĆ¢Ä‚¬Ä€¯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 systemĆ¢Ä‚¬Ä„¢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 'enlist' as it is used in the second paragraph?
- A. call into service
- B. write down
- C. send away
- D. put across
Correct Answer: A
Rationale: In the second paragraph, 'enlist' is used in the context of immune cells responding to an infection by calling other immune cells into service to address the issue. Therefore, the correct meaning of 'enlist' in this context is 'call into service.' The immune system works by activating and directing different cells to combat threats, highlighting the importance of mobilizing immune cells into action to fight infections.
Linking San Francisco to Marin County in California, the Golden Gate Bridge is one of the most famous bridges in the world. The bridge crosses over a narrow strait which connects the Pacific Ocean to San Francisco Bay. Prior to the bridge, people traveled by ferry boat across the strait.
Although most people thought a bridge was necessary to expedite travel, some residents of the
bay area felt the risk of building the bridge was too great. Joseph Strauss believed that nothing was impossible, and dreams would never come to fruition if risks weren't taken. So, he decided to gather the best and brightest builders, architects, and workers to embark on the challenge of
building a bridge across the Golden Gate Strait. With safety nets in place, the construction began in 1937. Building the anchorages first, the
builders then move on to the towers on each end, and then to the three-foot thick cables to support the suspension bridge. Lastly, workers labored to complete the roadway which became
the most dangerous and treacherous part of the entire task. The builders had to keep the bridge
balance, so it wouldn't fall into the bay.
Today, over sixty-five years later, the bridge remains a life-line for the people of the San Francisco Bay Area.
In the passage the word embark means to:
- A. Put or go on board a ship
- B. Remove the covering from a tree
- C. Speak harshly to others
- D. Being an undertaking
Correct Answer: D
Rationale: In the context provided in the passage, the word 'embark' is used to describe the action taken by Joseph Strauss to start on the challenge of building a bridge across the Golden Gate Strait. 'Embark' in this context means to undertake or start an important or challenging task. Therefore, the correct answer is D: 'Being an undertaking.' This choice aligns with the idea of starting a challenging project, as seen in the passage.
Lightning Strikes
The old wives' tale of "Lightning never strikes twice" has been proven untrue time and time again. Lightning forms from negative and positive charges within clouds and from the earth below. When these charges react with each other, the air between the cloud and the earth ionizes, which produces a lightning flash. Lightning is actually a series of multiple events consisting of a leader stroke of lightning, followed by as many as 40 smaller strokes of lightning. Being just split seconds apart, these strokes of lightning often reflect off the lining of the clouds.
Lightning rods that extend from above the roof to the ground protect buildings by forming a low resistance path for the lightning so that the lightning does not enter the building, but rather defuses as it penetrates the ground.
Some myths about lightning need to be explained. Lightning does strike tall buildings often, and during a particularly violent storm, a tall building may be hit by lightning several times. The safest place during a thunder and lightning storm is in a metal car or lying flat, face down, in the open, not under a tree as the myth suggests.
Many people believe that thunder and lightning are connected; however, this proves to be true only about 50% of the time, so if you're waiting for the clap of thunder, you're missing out on some exciting strokes of lightning!
Lightning causes injuries, deaths, and forest fires each year. However, some scientists reveal the positive aspects of lightning because it releases nitrogen into the atmosphere which the raindrops then deliver to earth to fertilize our soil.
Based on the provided information, the reader can conclude that lightning:
- A. Always consists of a single stroke
- B. Is harmless and does not pose any risk
- C. Consists of a main stroke and several smaller strokes
- D. Only occurs during thunderstorms
Correct Answer: C
Rationale: The correct answer is C: 'Consists of a main stroke and several smaller strokes'. The text explains that lightning is actually a series of multiple events, starting with a leader stroke followed by as many as 40 smaller strokes of lightning. This information contradicts choice A, which suggests lightning always consists of a single stroke. Choice B is incorrect because the text clearly states that lightning causes injuries, deaths, and forest fires, indicating that it poses risks. Choice D is incorrect as lightning rods protect buildings even when there is no thunderstorm, suggesting that lightning can occur independently of thunderstorms. Therefore, the conclusion drawn from the text is that lightning consists of a main stroke and several smaller strokes, making option C the correct answer.
Electrocardiogram
The rhythmic sounds of "beep... beep... beep..." signify the measurement of the heart muscle's strength. This rhythmic signal varies from person to person and is recorded as an electrocardiogram (ECG). Within the body, a complex array of systemic neural responses generates electric currents that can be detected on the skin's surface. When a person is connected to an amplifier, these impulses are captured by an electrocardiograph. Most of the information gathered pertains to the heart, as it emits electric currents in waves. This "wave of excitation" propagates through the heart wall and is associated with electrical changes. The process occurs in three distinct phases. First, the "wave of excitation," accompanied by an electrical change, lasts for about 1 to 2 seconds following the contraction of the cardiac muscle. These electrical impulses are rhythmically discharged from the sinoatrial (SA) node, which acts as the heart's natural pacemaker, signaling the atrium to contract. The peak of the ECG reading is attributed to the atrioventricular (AV) node, which triggers the excitation of the ventricles. Finally, as the ventricles relax, any changes in the wave pattern can alert trained medical personnel to potential abnormalities within the heart.
What is the best summary of the passage?
- A. Electric currents within the body are due to electrostatic charges set off by the heart. Medical staff are trained to recognize any abnormalities within the heart.
- B. Every individual has unique electric currents on the surface of the body. The ECG measures and records these electric currents.
- C. The ECG systematically and rather quickly measures the stages at which the "wave of excitation" occurs within the heart and records them. This wave has three distinct steps that spread from the SA node to the AV node.
- D. The ECG measures the electric currents within the body. These currents are detected on the surface of the body when the body is connected to an amplifier.
Correct Answer: C
Rationale: The correct answer is C because it accurately summarizes the passage by highlighting that the ECG systematically measures the stages of the 'wave of excitation' within the heart. This wave has three distinct steps that spread from the SA node to the AV node. The other options either focus on general information about electric currents or do not capture the specific details provided in the passage about the ECG and the heart's electrical activity.
People of Hispanic origin were on the North American continent centuries before settlers arrived
from Europe in the early 1600s and the thirteen colonies joined together to form the United
States in the late 1700s. The first census of the new nation was conducted in 1790, and counted about four million people, most of whom were white. Of the white citizens, more than 80%
traced their ancestry back to England. There were close to 700,000 slaves and about 60,000 "free Negroes". Only a few Native American Indians who paid taxes were included in the census count, but the total Native American population was probably about one million. By 1815, the population of the United States was 8.4 million. Over the next 100 years, the
country took in about 35 million immigrants, with the greatest numbers coming in the late 1800s and early 1900s. In 1882, 40,000 Chinese arrived, and between 1900 and 1907, there were more
than 30,000 Japanese immigrants. But by far, the largest numbers of the new immigrants were
from central, eastern, and southern Europe. An enormous amount of racial and ethnic assimilation has taken place in the United States. In 1908, play-write Israel Zangwill first used the term "melting pot" to describe the concept of a place where many races melted in a crucible and re-formed to populate a new land. Some years during the first two decades of the 20th century, there were as many as one million new
immigrants per year, an astonishing 1 percent of the total population of the United States.
In 1921, however, the country began to limit immigration, and the Immigration Act of 1924
virtually closed the door. The total number of immigrants admitted per year dropped from as many as a million to only 150,000. A quota system was established that specified the number of
immigrants that could come from each country. It heavily favored immigrants from northern and western Europe and severely limited everyone else. This system remained in effect until 1965, although after World War II, several exceptions were made to the quota system to allow in
groups of refugees
According to the passage, which ancestry predominated at the time of the first census?
- A. Native Americans
- B. Negroes
- C. English
- D. Hispanic
Correct Answer: C
Rationale: At the time of the first census in 1790, the passage states that more than 80% of the white citizens traced their ancestry back to England. This indicates that English ancestry predominated at that time. The passage also mentions the presence of Native Americans, Negroes, and immigrants from various other regions, but in terms of predominant ancestry, it was the English.