Reading Comprehension Related

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 are the three phases of the "wave of excitation"?

• A. The discharge from the SA node, the peak ECG, and the excitement of the ventricle.
• B. The excitement of the ventricle, the relaxing of the ventricle, and the systemic neural response.
• C. The contraction of the atrium, the relaxation of the atrium, and the contraction of the ventricle.
• D. The excitation of the atrium, the excitement of the ventricle, and the relaxing of the ventricle.

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.

What is the main idea of the passage?

• A. Trains and ambulances produce specific sounds
• B. Low-frequency waves produce high-pitched sounds.
• C. High-frequency waves produce low-pitched sounds.
• D. The Doppler Effect explains why sound is heard more strongly initially and then faintly after a moving object has passed.

Food
Food and drink are necessary and desirable, but their
abuse can cause serious physical and metal problem.
Many physicians believe that overeating is one of the
country'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 driver's
contribution to highway death, 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. Accompanying
• B. Quiet
• C. Separate
• D. Unpredictable

It is a well-known fact that it takes the Earth approximately 365 days to orbit the Sun. At the same time, the Earth revolves or spins around itself over the course of 24 hours, which explains why we experience day and night. One half of the Earth is always facing the Sun, while the other half is facing away. As a result, different time zones divide the globe. Moving suddenly from one time zone to another, such as when flying from Asia to North America, can cause jet lag. People often feel tired, wake up suddenly during the night, and cannot return to sleep. It takes time to adjust to a new time zone. Another important factor to consider is the slight tilt of the Earth toward the Sun. The Earth does not stand straight but leans slightly to one side. Therefore, when it revolves around the Sun, the middle part of the Earth is always closer to the Sun and receives more heat. This area is called the equator, and the regions above and below it are known as the tropics. Countries located in the tropics receive a consistent amount of daylight throughout the year, with the Sun rising at 6 AM and setting at 6 PM. In contrast, the tips of the Earth, or the poles, receive hardly any light because they are so far from the Sun. There are two main seasons at the poles: 6 months of summer, when the Sun is always shining (even at night), and 6 months of winter, characterized by constant darkness. Between the tropics and the poles lies the temperate zone, where there are four distinct seasons. The Sun rises and sets at different times throughout the year. In spring and summer, it gets light earlier; in fall and winter, it gets dark earlier. People living in temperate zones take advantage of this variation to maximize their daylight exposure. At the beginning of spring, countries in Europe and North America readjust their clocks by moving them an hour ahead. As a result, the Sun does not set around 7 or 8 PM as usual, but an hour later. This practice is called Daylight Savings Time (DST) and lasts until the beginning of fall, when people move their clocks back one hour to Standard or Regular Time. It is believed that Benjamin Franklin first suggested the introduction of Daylight Savings Time in the 18th century, but the first serious proposal came in 1907 from William Willet. However, his idea was shelved by the British government, which deemed it unnecessary. Daylight Savings Time was first implemented by the German government in 1916 in order to save energy during World War I. Shortly after, the United Kingdom followed suit, with the United States doing the same in 1918. The law was unpopular, as people had to wake up earlier, leading many to experience a feeling similar to jet lag. However, the energy crisis of the 1970s forced the U.S. to establish Daylight Savings Time as law. Studies showed that the introduction of Daylight Savings Time in the spring saved the U.S. 10,000 barrels of oil per day between 1974 and 1975. It also prevented 2,000 traffic injuries and 50 traffic-related deaths, saving the country $28 million. Currently, Americans switch to Daylight Savings Time on the first Sunday in April and revert to Standard Time on the last Sunday in October. As of 2007, the time adjustments occur even earlier in March and November.

Which part of the Earth is closest to the Sun?

• A. The Equator
• B. The tropics
• C. The temperate zone
• D. The Poles

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"