Alzheimer's disease impairs a person's ability to recall memories, both distant and as recent as a few hours before. Although there is not yet a cure for the illness, there may be hope for a cure with a protein called nerve growth factor. The protein is produced by 5 nerve cells in the same region of the brain where Alzheimer's occurs. Based on this relationship, scientists from the University of Lund in Sweden and the University of California at San Diego designed an experiment to test whether doses of nerve growth factor could reverse the effects of memory loss caused by Alzheimer's. Using a 10 group of rats with impaired memory, the scientists gave half of the rats doses of nerve growth factor while giving the other half a blood protein as a placebo, thus creating a control group. At the end of the four-week test, the rats given the nerve growth factor performed equally to rats with normal memory abilities. While the experiments 15 do not show that nerve growth factor can stop the general process of deterioration caused by Alzheimer's, they do show potential as a means to slowing the process significantly.
1. With what topic is this passage mainlyconcerned?
2. The word "impairs" in line 1 is most similar to which of the following?
3. According to the passage, where is nerve growth factor produced in the body?
4. Which of the following is closest in meaning to the word "region" as used in line 5?
5. Which of the following is closest in meaning to the word "doses" in line 8?
6. Which of the following could best replace the word "reverse" as used in line 9?
7. Which of the following can be inferred from the passage?
8. The passage most closely resembles which of the following patterns of organization?
9. Which of the following is closest in meaning to the word "deterioration" in line 16?
10. Which of the following could best replace the word "potential" in line 16?
11. Which of the following could best replace the word "significantly" in line 17?
12. The relationship between nerve growth factor and a protein is similar to the relationship between Alzheimer's and
