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进行理化检验样品抽样时，样品应具有哪些特性
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How long do normal mice live according to the passage？
What can we learn from the experiment？
Scientists can learn about man by studying animals, such as mice, rats and monkeys. The scientists in a laboratory areexperimenting on mice and they are studying the relationship between diet and health. In this experiment, the scientists are studying the relationship between the amount of food the mice can eat and theirhealth. The mice are in three groups. All these groups are receiving the same healthy diet. But the amount of food that eachgroup is receiving is different. The first group is eating one cup of food each day, the second two cups, and the third threecups. After three years, the healthiest group is the one that is only eating one cup of food each day. The mice in this group arethinner than normal mice but they are more active. Most of the day, they are running, playing with one another, and using theequipment in their cages. Also, they are living longer. Mice usually live for two years, while most of the mice in this groupare still alive after three years. The second group of mice is of normal weight. They are healthy, too. They are active, but not as active as the thinnermice. But they are only living about two years. The last group of mice is receiving more food than the other two groups. Most of the day, these mice are eating orsleeping. They are not active. These mice are living longer than the scientists thought —about a year and a half, but they arenot healthy. The are sick more often than the other two groups. The first group is the thinnest mainly because
What is professor Potrykus ’ s attitude towards the breeding of Golden Rice？
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