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Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42. Fungi, of which there are over 100,000 species, including yeasts and other single-celled organisms as well as the common molds and mushrooms, were formerly classified as members of the plant kingdom. However, in reality they are very different from plants and today they are placed in a separate group altogether. The principal reason for this is that none of them possesses chlorophyll, and since they cannot synthesize their own carbohydrates, they obtain their supplies either from the breakdown of dead organic matter or from other living organisms. Furthermore the walls of fungal cells are not made of cellulose, as those of plants are, but of another complex sugar like polymer called chitin, the material from which the hard outer skeletons of shrimps, spiders, and insects are made. The difference between the chemical composition of the cell walls of fungi and those of plants is of enormous importance because it enables the tips of the growing hyphae, the threadlike cells of the fungus, to secrete enzymes that break down the walls of plant cells without having any effect on those of the fungus itself. It is these cellulose-destroying enzymes that enable fungi to attack anything made from wood, wood pulp, cotton, flax, or other plant material. The destructive power of fungi is impressive. They are a major cause of structural damage to building timbers, a cause of disease in animals and humans, and one of the greatest causes of agricultural losses. Entire crops can be wiped out by fungal attacks both before and after harvesting. Some fungi can grow at +50°C, while others can grow at -5°c, so even food in cold storage may not be completely safe from them. On the other hand, fungi bring about the decomposition of dead organic matter, thus enriching the soil and returning carbon dioxide to the atmosphere. They also enter into a number of mutually beneficial relationships with plants and other organisms. In addition, fungi are the source of many of the most potent antibiotics used in clinical medicine, including penicillin. What does paragraph 1 mainly discuss?

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Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 31 to 35. Saving energy means saving money and conserving our natural resources. Homeowners and renters know this basic fact, but they often don't know what kinds of adjustments they can make in their homes and apartments that will result in savings. For those willing to spend some time and money to reap long-term energy savings, an energy audit is the way to go. An energy auditor will come into your home and assess its energy efficiency. The auditor will pinpoint areas of your home that use the most energy and offer solutions to lower your energy use and costs. Trained energy auditors know what to look for and can locate a variety of flaws that may be resulting in energy inefficiency, including inadequate insulation, construction flaws, and uneven heat distribution. There are quicker and less costly measures that can be taken as well. One way to save money is to replace incandescent lights with fluorescents. This can result in a savings of more than 50% on your monthly lighting costs. When it's time to replace old appliances, it's wise to spend a bit more for an energy-efficient model, and be sure that you are taking advantage of energy-saving settings already on your current refrigerator, dishwasher, washing machine, or dryer. Windows provide another opportunity to cut your energy costs. Caulk old windows that might be leaky to prevent drafts, and choose double-paned windows if you're building an addition or replacing old windows. Most areas of your home or apartment offer opportunities to save energy and money. The results are significant and are well worth the effort. Which two main organizational schemes can be identified in this passage?

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Cho các thông tin ở bảng dưới đây về chuỗi thức ăn và năng lượng tương ứng chứa trong mỗi bậc dinh dưỡng mà học sinh A đã tiến hành đo lường ở một khu vực sinh thái. Chuỗi thức ăn →Cỏ →Cào cào →Chim sâu →Rắn Năng lượng (calo) 2,2.106 1,1.104 0,55.103 0,5.102 Một học sinh khác (học sinh B) sử dụng các số liệu thu thập được và tiến hành tính toán cũng như kết luận về quá trình nghiên cứu của học sinh A và đưa ra một số nhận xét sau: I. Hiệu suất chuyển hóa thành sinh khối giữa các bậc dinh dưỡng liền kề có giá trị cao nhất nằm ở sinh vật tiêu thụ bậc 3. II. Giá trị hiệu suất sinh thái của bậc dinh dưỡng thứ 2 so với bậc dinh dưỡng thứ nhất là5×10−3 . III. Một phần lớn năng lượng được sinh vật sản xuất đồng hóa được sẽ được dùng vào việc xây dựng sinh khối của bản thân nó, hô hấp cung cấp năng lượng cho hoạt động sống của chúng và chỉ một phần nhỏ được chuyển sang bậc dinh dưỡng kế tiếp. IV. Với hiệu suất sinh thái ở chuỗi thức ăn này, chuỗi có thể kéo dài thêm hàng chục mắt xích tiếp theo. Trong số các nhận định kể trên, có bao nhiêu nhận định là chính xác?

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