在分类等级中，最大单位和基本单位分别是（ ）
A．门、目
B．界、种
C．纲、属
D．科、目
生物分类单位由大到小是界、门、纲、目、科、属、种．界是最大的分类单位，最基本的分类单位是种．分类单位越大，生物的相似程度越少，共同特征就越少，包含的生物种类就越多，生物的亲缘关系就越远；分类单位越小，生物的相似程度越多，共同特征就越多，包含的生物种类就越少，生物的亲缘关系就越近．如人种：黄种人、白种人、黑种人，他们相似程度多，亲缘关系就近．
故选：B．
| |
| 1. What does the Relex Company make? | |
[ ] | |
| A. Lights. B. Cameras. C. Batteries. D. Lamps. | |
| 2. When Sarah got the camera, _______. | |
[ ] | |
| A. it worked very well B. it didn't have any batteries C. the light metre doesn't work well D. it didn't take good photos | |
| 3. What's wrong with Sarah's photos? | |
[ ] | |
| A. They aren't light enough. B. They aren't dark enough. C. You can't see them D. They are too colourful. | |
| 4. How old is Sarah's camera? | |
[ ] | |
| A. One. B. Five. C. Six. D. About six. | |
| 5. Sarah plans to get a new camera, _______. | |
[ ] | |
| A. so she doesn't need her old one B. and she wants Relex to give it to her for free C. and she wants to send the old one to her friend D. but she still wants her old one repaired |