下列金属中，哪一项的碳含量是2％～4.3％。（）_海管混凝土配重工_全学科试题题库

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下列金属中，哪一项的碳含量是2％～4.3％。（）
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Facts About FoodEverywhere on earth there are"food specialists"with opposite (or different) opinions on the best kinds of nutrition for various purposes. A lot of people believe that the healthiest diets are high in fiber ,vitamins ,and minerals but low in fat ,cholesterol ,sugar,and salt. Some nutritionists say the perfect eating plan contains mostly carbohydrates without much protein. In contrast , other scientists say people need high-protein meals with meat, chicken , fish , or milk products and only small amounts of grains , potatoes , breads , rice , and noodles. One famous diet plan allows only certain foods at certain times-protein with protein, carbohydrates with carbohydrates , fruits alone , and so on. Some eaters stay away from all meat and maybe even fish and milk products. They get their protein from plants , mostly beans. Others want only high-fiber food. These people may not eat white bread or white rice or even cooked vegetables. So what is the best way to eat and be healthy? The discussion of food facts will go on far into the future.The necessary substances and elements for human life and health are water, protein, carbohydrates ,fats , vitamins, and minerals. Most kinds of food contain some or all of the required nutrients , but these substances have different effects on people. Various ingredients and dishes affect the mind in different ways. and some kinds of nourishment have better effects on the brain than others. For instance. can broccoli increase brain power? Maybe so. Low levels of some of the B vitamins can cause a decrease in memory and thinking ability , nutritionists say, but dark green vegetables , like broccoli , contain a lot of these nutrients. Another example of a"memory helper"is lecithin-a substance from soybeans , also found in high-fiber foods like nuts and whole grains. High-protein foods influence the mind in more helpful ways than dishes high in sugar and carbohydrates. And the caffeine in coffee or tea may help thinking. Of course , its effects don't last long.In many places outside big cities , food with more than four legs is part of good, healthy home cooking. Fried or grilled ants are a tasty but expensive snack in Colombia , South America. In various parts of Mexico , over 300 types of insects serveas food. In southern Africa. many people like to eat at least one kind of caterpillar or worm. They enjoy it fried , dried , or cooked in tomato sauce. In Thailand , cooks create a spicy hot pepper sauce with water bugs. In Vietnam , grasshoppers filled with peanuts are a special dish. And in some regions of China,bugs are not only a part of meals but an important ingredient in medicine too. Most kinds of insects have high nutritional value. They contain a l0t of protein , vitamins , and minerals. Many people like their taste. They are everywhere on the planet. They add to the variety of people' s diets. For several reasons , insects are an important kind of food in the global diet , and they may become a more common ingredient in the future.The growing similarities in diet and eating habits around the world are influencing people of various cultures in different ways. For example, Western foods are damaging health in the industrialized island country of Japan. Instead of small meals of seafood , rice , and vegetables ,the typical Japanese diet ow includes large amounts of meat ,dairy products. And desserts like tiramisu , a rich Italian dish full of chocolate , cheese , and sugar. According to Japanese health researchers , such changes in eating habits are related to a great increase in health problems such as heart disease , strokes , cancer , and diabetes. On the other hand , the changing global diet is having the opposite effect on the people in the Czech Republic. The government of this European nation no longer supports meat and dairy products financially , so the cost of these foods is going up. In contrast , fresh fruits and vegetables are becoming more widely available from private markets and stands. Cooks are even serving salads to schoolchildren ,and families are eating healthier home-cooked meals. For these reasons ,fewer Czech men are having heart attacks , the women are l0sing a l0t of weight , and most people are living healthier lives.Decide whether the following statements are true or false. Write"T"for True and"F"for False on the Answer Sheet.6. The best way to eat is to eat only small amounts of carbohydrates.7. Most kinds of food contain fats , vitamins and minerals.8. High-fiber food like nuts and whole grains can influence people' s memory.9. Four legs insects serve as food in many places in the world.10. Japanese health researchers consider Italian tiramisu is the key factor that relates to health problems in Japan.

属于天然来源的抗寄生虫药物有

科学家将棕鼠卵丘细胞的核物质注入内部已经抽空的黑鼠卵细胞内，激活以后，移入白鼠的子宫，白鼠最后产下一只克隆鼠。这只克隆鼠的体色和性别是（）