Passage
"The use of animal models is valuable in understanding the impact of cocaine addiction on the human brain. In these studies, researchers insert a needle directly into specific areas of a mouse's brain that are involved in dopamine pathways. The needle is connected to a lever, which dispenses cocaine into the brain whenever the mouse activates it. Mice quickly learn that pressing the lever results in a pleasurable sensation. To investigate the influence of different environmental conditions on mice's addiction to cocaine, a scientist conducted a study. One group of cages provided minimal resources, containing only the lever and limited food and water. The other group of cages offered an enriched environment, including sweetened water, ample food, and an exercise wheel for the mice. Additionally, half of the mice in each condition were raised in isolation, while the other half were raised in a typical family setting. The scientist first trained the mice to press the lever to receive a cocaine injection and then measured the amount of cocaine the mice self-administered over a two-week period. Table 1 presents the average doses of self-administered cocaine (in milligrams) for each condition."
Question for Practice Passage Test - 13
Try yourself:What is the purpose of using animal models in the study of cocaine addiction?
Explanation
The passage states that animal models provide useful insights into the effects of cocaine addiction on the human brain. Therefore, the purpose of using animal models in this study is to understand the impact of cocaine addiction on the human brain.
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Question for Practice Passage Test - 13
Try yourself:What is the purpose of placing an injection needle in a mouse's brain in the study?
Explanation
The passage mentions that the injection needle is connected to a lever, which releases cocaine into the mouse's brain whenever it is activated. Therefore, the purpose of placing the injection needle is to deliver cocaine to the mouse's brain.
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Question for Practice Passage Test - 13
Try yourself:What were the two different sets of environmental conditions provided to the mice?
Explanation
The passage mentions that one group of cages was very bare, containing only the lever and minimal food and water, while the other group of cages was enriched, offering sweetened water, plenty of food, and an exercise wheel. These are the two different sets of environmental conditions provided to the mice.
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Question for Practice Passage Test - 13
Try yourself:What was the factor that varied between the mice in each cage condition?
Explanation
The passage states that half of the mice in each cage condition were reared in isolation, while the other half were reared in a typical family setting. Therefore, the factor that varied between the mice in each cage condition was their rearing conditions.
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Question for Practice Passage Test - 13
Try yourself:What was the dependent variable measured in the study?
Explanation
The passage mentions that the scientist measured the amount of cocaine the mice self-administered over a two-week period. Therefore, the dependent variable in the study was the average doses of self-administered cocaine.
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