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2. Trong 1 quần xã ruộng lúa gồm nhiều quần thể sinh vật cùng sinh sống, trong đó: - Tảo là thức ăn của cá nhỏ - Mùn bã hữu cơ là thức ăn của cá nhỏ và ốc - Lúa là thức ăn của châu chấu và chuột. - Ếch nhái ăn cá nhỏ, ốc và châu chấu. - Rắn ăn châu chấu, ếch nhái và chuột a. Có mấy loại chuỗi thức ăn trong quần xã trên? Mỗi loại chuỗi thức ăn cho 2 ví dụ? b. Nếu loài ếch nhái bị bắt gần hết thì quần xã trên sẽ biến động như thế nào? Giải thích?
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X. Read the passage and choose the correct answer Television is very popular and even has some benefits for kids. It helps very young children learn the letters of alphabets and helps other kids learn about science, cultures, and world events. However, researchers show that too much TV is bad for children. For one thing, there is a link between watching more than four hours of TV a day and being overweight. For another thing, many TV shows are violent and upsetting. Watching these shows may cause kids to be more fearful. And of course, more time in front of the TV means less time to study. Too much TV also be the cause of lower grades. Experts don’t agree on the solution to the problems. Some say that kids should watch only educational programs; others say kids should watch no TV at all. And others suggest teaching them to watch TV as occasional entertainment, not as an every day hobby. 1. What is the passage mainly about? A. Benefits of kids’ TV shows B. effects of TV on kids C. why kids love TV D. why kids shouldn’t watch TV 2. According to the passage, watching a lot of TV may ____ A. Cause weight problems in children C. cause children to be more famous B. Cause children to get better grades D. cause students to study more 3. The word “them” in paragraph 3 is closest in meaning to A. Programs B. experts C. kids D. problems 4. The word “occasional” in paragraph 3 is closest in meaning to A. Very often B. not very often C. always D. every day 5. What can be inferred from the passage? A. TV is always bad for children C. TV is only good for entertainment B. Kids should watch only educational shows D. television has some benefits along with problems

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