Extract:
Sickle-Cell Anemia
Healthy red blood cells are shaped like a disc. Each cell contains the protein hemoglobin, which carries oxygen throughout the body. In some people, a crescent shaped cell forms instead of the normal discshaped cell. The crescent-shaped cells contain abnormal hemoglobin. These sickle-shaped cells are fragile and are unable to carry oxygen properly throughout the body.
Sickle-cell anemia is an inherited disease that affects about 72,000 people in the United States. It is more common among people of South American or African descent. The genes for sickle-cell anemia are inherited from both parents. When both parents carry a gene for the trait for sickle-cell, there is a one in four chance that they will pass the disease on to their children.
Symptoms of sickle-cell anemia can include sudden occurrences of extreme abdominal and back pain, bone pain, fever, fatigue, and a rapid heart rate. One patient compared the pain in his back to a jackhammer and said the pain could take over his entire body. Another patient, an eight-year-old girl, described fevers and the feeling of someone squeezing her arms and legs.
Cycles of symptoms are often unpredictable and can occur infrequently or almost constantly. Some people who are affected report weekly occurrences of persistent pain, while others report occurrences once a month. Some report that relief comes only by using powerful painkillers. For others, relief comes with bed rest and a hot-water bottle. Most agree that while the challenges of managing sickle-cell anemia are great, with diligent care, it can be managed.
What is the main idea of the passage?
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A
Bone pain is a typical sign of sickle-cell anemia.
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B
Without enough oxygen, the body can break down.
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C
Genetically inherited diseases affect thousands.
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D
Sickle-cell anemia is a painful, inherited disease.
The main idea is that sickle-cell anemia is a painful, inherited disease, capturing both its genetic transmission mechanism and its defining symptom of severe, unpredictable pain.
A) Bone pain is a typical sign of sickle-cell anemia
This is too narrow, while bone pain appears among symptoms, it represents only one manifestation of a broader painful condition. The passage emphasizes multiple pain types (abdominal, back, bone) and vivid patient descriptions beyond bone pain alone.
B) Without enough oxygen, the body can break down
This overgeneralizes a secondary mechanism. While sickle cells "are unable to carry oxygen properly," this physiological detail supports the disease description rather than constituting the passage's central focus.
C) Genetically inherited diseases affect thousands
This is too broad, the passage focuses specifically on sickle-cell anemia's characteristics, not genetic diseases generally. The 72,000 statistic applies only to this single condition.
D) Sickle-cell anemia is a painful, inherited disease
This captures the two dominant themes developed across paragraphs: inheritance pattern ("genes... inherited from both parents," "one in four chance") and pain severity ("extreme abdominal and back pain," jackhammer analogy, squeezing sensation descriptions, unpredictable cycles requiring "powerful painkillers").
Conclusion
Main ideas must encompass a passage's comprehensive focus, not isolated details or overly broad generalizations. Option D successfully integrates the disease's genetic basis with its defining clinical feature (pain) that dominates patient experiences described throughout the text.