图甲表示某种高等动物（体细胞染色体数目为2n）在繁殖和个体发育过程中核DNA数目的变化，图乙表示该种动物体内细胞进行某种细胞分裂时，核DNA、染色体、染色单体数目变化，图丙表示某一动物个体体内细胞处于若干特定细胞分裂时期的模式图，请据图分析回答：
图甲中，表示减数分裂过程中DNA数目变化的是（）段。gh段细胞的主要特点是（）。从染色体角度看，hi段与cd段中对应的时期相比，相同点是（），不同点是（）。减数分裂中，染色体数目的减半发生在（）段（用图中的标号回答），减半的原因是（）
参考答案：a～d；染色体着丝点排列在赤道板；着丝点分裂，姐妹染色单体分离；前者细胞中具有同源染色体，后者没有；bc；同源染色体分离，进入两个子细胞
| 阅读理解。 |
| When you go looking for fossils, don't take too many things with you. A bag full of heavy fossils is quite enough to carry home. But you need to remember: 1.  Take a hammer with you for breaking open rocks (岩石). A hammer is the best kind to use. A pair of glasses will stop flying pieces of stones from hurting your eyes. 2.  A hand lens is useful. You might find fossils that are too small to see clearly. With a hand lens you can examine the small things better. 3.  Take a map of the area you're visiting to show you where you might find the fossils, plus a ruler for measuring(测量) the fossils you find. 4.  A camera will be useful for photographing interesting rocks which stand up out of the ground. That'll help you to remember where you found the fossils. 5.  Number your fossils and wrap (包、裹) them in newspapers before putting them into your bag. 6.  Make sure that your clothing is suitable for the weather in whatever kind of countryside you are visiting. 7.  You have to take a notebook and pencils. As soon as you find something interesting, take a note of where you found it and the kind of rock in which it was found. |
| 1. Because fossils are very heavy, you need to _______. |
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| A. take fewer things if possible B. number the fossils which have been collected C. carry a large hammer D. wear light clothing |
| 2. The word "them" in Point 5 means _______. |
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| A. newspapers B. photos C. fossils D. rocks |
| 3. Which of the following is TRUE according to the passage? |
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| A. A hand lens is used to read the map. B. Newspapers can give some new information. C. A camera is used to take photos of the people who look for fossils. D. A notebook and pencils can be used to record the kinds of rock in which fossils were found. |
| 4. This passage mainly shows the reader _______. |
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| A. where to look for fossils B. what is needed when looking for fossils C. how to look for fossils D. when it is the best time to look for fossils |