Passage 9

Sometimes people worry about the germs that they come into contact with daily. In fact, most people would be surprised to learn just how many microbes actually inhabit  a human’s body at any given time, in addition to the larger visitors that come around occasionally. Such natural species that regularly come into contact with our bodies include mites, lice, yeast, and fungus, just to name a few. We are, in fact, an ecosystem much like a rain forest is to the natural flora and fauna that call it home.

Lice, or nits, are particularly horrible to even think about. To learn that one’s child has been found in school with head lice can cause trauma and shame.  People think that having lice is a symptom of being unclean, although one can be infected by contact with somebody else who has them. Although lice are not that common in general circles, chil-dren can easily acquire them just because of their  close contact with other children at school or play. Some large cities host high-priced nit pickers who make a living removing head lice from children.

Mites on the human body are much more common, and cleanliness does not eliminate the chance of having them. They are also microscopic, so they are invisible to the naked eye. There are a number of different species

of mites, two of which have the human face as their natural habitat, particularly the skin of the forehead. Others  are very content among human hair, living among the follicles of the eyelashes, eyebrows, and scalp hair.

Not all such inhabitants are harmful. In fact, even the annoying mite lives on dead skin cells, actually doing us a favor by removing them. The dreaded dust mite, for example, blamed for causing allergies, removes dead skin from bed coverings. And harmless bacteria often keep potentially harmful bacteria from being able to survive. So people should not try to eliminate mites from their bodies, although some have tried. Some sufferers of obsessive/compulsive disorder have scrubbed themselves raw trying to eliminate all scavengers from their bodies, only to damage their skin, and all to no avail.

Certain types of yeast also regularly live on the human body, sometimes causing annoyances. One common type lives on the oil produced in the skin of the face or scalp, causing a condition known as pityriasis versicolor, which is a scaling and discoloration of the skin.

Ailments such as athlete’s foot are caused by a fungus that grows in warm, moist conditions. To avoid them or avoid a recurrence patients are encouraged keep their feet dry and cool, which of course may not be easy, depending on one’s work or personal habits. Ringworm is also a fungus acquired by con-tact with keratin-rich soil in many parts of the world.

Besides the tiny inhabitants, we are also regularly harassed by insects that feed off of our bodies, like mosquitoes, ticks, and fleas, which sometimes deposit harmful illnesses at the same time they probe the skin for the blood on which they live. Mosquitoes have been known to cause malaria and yellow fever as well as encephalitis. Fleas have transmitted bubonic plague, and ticks have caused lime disease.

Just like a river, an ocean, a rain forest, or any other ecological wonder in which numerous species survive, feeding upon other inhabitants, our bodies are natural providers of nutrition and life for various small and microscopic species.

1. The word inhabit in the second sentence is closest in meaning to

2. The author’s main point is

3. The author infers that lice and mites are different in that

4. The word shame in the second paragraph is closest in meaning to

5. The word their in the second paragraph refers to

6. Where, in the third paragraph, could the following sentence be inserted logically?

In fact, one mite is generally about one-fourth the size of a period on a page of text.

7. The word others in the third paragraph refers to

8. The author indicates that lice are also known as

9. The author indicates that a nit picker is

10. The author infers that

11. What does the author mean by the statement Not all such inhabitants are harmful at the beginning of the fourth paragraph?

Passage 10

Sinkholes may occur  slowly and be completely harmless or may quickly cause devastating  damage. It is interesting that sinkholes may be caused by two opposite conditions — extreme drought or too much rain.

As depicted in the drawing, under the sandy surface soil is a layer of clay and then a layer of limestone. Sinkholes generally occur only in areas where the geology has this composi-tion. Within the limestone areas are pockets of water and air. When the underground aquifer is full of ground water, the pockets are generally filled with water and perhaps air above the water. But when there is too much rain or not enough rain, the caverns may become unstable. When there is too much, the cavern walls can be broken through because of excess pressure, and when there is too little, the cavern walls can collapse because there is not enough internal pressure to withstand the weight from above. When that occurs, the cavern collapses, and the sandy soil close to the surface seeps or pours into the cavern. The speed of the collapse and amount of damage depends on the size of the collapsing cavern.

In drought  conditions, sinkholes become more common over time. They may harmlessly appear in a lawn and then stop.

Sometimes, small sinkholes recur or continue to eat soil for years without causing any damage. But at other times they open in the middle of streets, surprising drivers and swallowing cars, or in residential areas, swallowing houses. Sinkholes are not discriminating.  They have swallowed  small in-expensive homes, as well as huge homes worth millions of dollars. It is very rare for people to be hurt when it occurs, because it usually occurs over some length of time and is noisy as the ground becomes unstable.

Sinkholes have also swallowed lakes. There are areas in Florida where 40 or more homes had been built around a beautiful lake. One day, the entire lake disappeared because the cavern beneath the ground opened. Instead of sand being above the cavern, there was water, which flowed into the cavern, leaving behind dead and dying fish and plants and docks that led to nowhere. In one neighborhood, the neighbors managed to plug the hole in the lake with a huge block of concrete, and rain eventually filled the lake. But their efforts were to no avail because several years later the lake disappeared again.

Sinkholes are a natural phenomenon caused in particular geological areas by particular events. Unfortunately, even knowing the cause and having time to plan, it is not possible to stop a sinkhole.

1. The word occur in the first sentence is closest in meaning to

2. The word devastating in the first sentence is closest in meaning to

3. A good title for this passage would be

4. The author states that sinkholes can be caused by

5. The author implies that sinkholes

6. The author indicates that the layers of material in soil from the top down are

7. The word drought in paragraph three is closest in meaning to

8. The word discriminating in the third paragraph is closest in meaning to

9. The word swallowed in paragraph three is closest in meaning to

10. According to the passage, caverns are normally filled with

11. An example of a harmless sinkhole would be

12. According to the passage, how successful was the attempt to replace a lake by plugging the hole?

Passage 11

It was previously believed that dinosaurs were cold-blooded creatures, like reptiles. However, a recent discovery has led re-searchers to believe they  may have been warm-blooded. The fossilized remains of a 66 million-year-old dinosaur’s heart were discovered and examined by x-ray. The basis for the analysis that they were warm-blooded is the number of chambers in the heart as well as the existence of a single aorta.

Most reptiles have three chambers in their hearts, although some do have four. But those that have four chambers, such as the crocodile, have two arteries to mix the oxy-gen-heavy blood with oxygen-lean blood. Reptiles are cold-blooded, meaning that they are dependent on the environment for body heat. Yet the fossilized heart had four chambers in the heart as well as a single aorta. The single aorta means that the oxygen-rich blood was completely separated from the oxygen-poor blood and sent through the aorta to all parts of the body.

Mammals, on the other hand, are warm-blooded, meaning that they generate  their own body heat and are thus more tolerant of temperature extremes. Birds and mammals, because they are warm blooded, move more swiftly and have greater physical endurance than reptiles.

Scientists believe that the evidence now points to the idea that all dinosaurs were actually warm-blooded. Ironically, the particular dinosaur in which the discovery was made was a Tescelosaurus, which translates to “marvelous lizard.” A lizard, of course, is reptile.

1. The word they in the second sentence refers to

2. According to the author, what theory was previously held and now is being questioned?

3. What is the basis of the researchers’ new theory?

4. The author implies that reptiles

5. The word generate in paragraph three is closest in meaning to

6. The author implies that birds

7. What does the author imply by the sentence:

Ironically, the particular dinosaur in which the discovery was made was a Tescelosaurus, which translates to “marvelous lizard.”

Passage 12

Many people suffer from an ailment  of the gallbladder, which  occurs when stones form within the organ. The gallbladder is a small sac in the upper-right section of the abdomen, beneath the liver and near the pancreas. Its function is to store bile, which is produced by the liver to help digest fat and absorb vitamins and minerals. Bile consists mainly of water, cholesterol, lipids (fats), bile salts,  which are natural detergents that break up fat, and bilirubin,  which is a pigment that gives bile its greenish-yellow color.

Gallstones form when the cholesterol and the bilirubin form crystals, which then fuse  in the gallbladder to form the stones. They range in size from tiny specks the size of grains of sand to stones as large as golf balls, although most are quite small. Sometimes the crystals accumulate but do not form stones. But even then, they form a sludge that causes indigestion and discomfort, which is not as serious as the symptoms that stones cause.

The great majority of gallstones are made of cholesterol, but some consist of bile pigment. The former are produced when the bile is too rich in cholesterol or the gallbladder is not functioning properly, and they generally occur in people within the risk factors.

Gallstones can irritate the lining of the gall-bladder, causing chronic inflammation and infection, resulting in pain in the abdominal area. An acute gallstone attack occurs when the gallbladder contracts while squeezing its bile through the cystic duct, and one or more stones lodge in the duct. The muscles in the duct wall then contract in an attempt to dislodge the stone, causing severe pain. If they are not dislodged, the bile backs up into the liver and eventually the bloodstream.

Risk groups include people who are over-weight; people who fast habitually or are on long-term extremely low-calorie diets; pregnant women; people with diabetes; females between the ages of 20 and 60; native American men or Pima Indian women of Arizona; and Mexican-American men or women. As anybody ages, the chance of gallstones increases, with 10 percent of all men and 20 percent of women having gall-stones by age 60.

Gallstones are diagnosed with an ultrasound, which is a device that transmits sound waves into the body and returns a depiction of the organ. Even patients with gallstones generally do not need treatment unless the stones are causing chronic symptoms. Large stones can be crushed through a procedure called shock wave lithotripsy, but the fragments then must exit the body, which can be uncomfortable. The most common treatment is to remove the gallbladder entirely. The body gets along quite well with no gallbladder because it is simply a storage area. The manufacture of bile in the liver goes on just the same, al-though there is no bile present in the event it is needed quickly. For that reason, patients are urged to avoid excessively fatty foods.

1. The word ailment in the first sentence is closest in meaning to

2. The word which in the first sentence refers to

3. The author implies in the first paragraph that sludge is similar to

4. The word fuse in the second paragraph is closest in meaning to

5. The author implies in the first paragraph that bile salts are similar to

6. The author implies in the first paragraph that bilirubin is similar to

7. The author indicates that crystals of cholesterol and bilirubin that do not fuse cause

8. The author states that most gallstones are caused by

9. The word irritate in the fourth paragraph is closest in meaning to

10. The word dislodge in the fourth paragraph is closest in meaning to

11. The author implies that most severe attacks occur when a stone becomes stuck in the

12. One common cause of gallstones is

13. All of the following people are potentially at high risk of getting gallstones except

14. The word depiction in the last paragraph is closest in meaning to

15. The word it in the last paragraph refers to