动物、植物、微生物物种水平的生物多样性被称为（）。A、物种多样性 B、遗传多样性 C 发布时间：2017-07-25 13:02 │ 来源：www.tikuol.com 题型：单项选择题 问题： 动物、植物、微生物物种水平的生物多样性被称为（）。A、物种多样性B、遗传多样性C、基因多样性D、生态系统多样性
题型：单项选择题 完型填空。 Mark 1 home from school one day when he noticed a boy ahead of him. He had tripped and droppedall of the books he was carrying, 2 two sweaters, a baseball bat and a glove. Mark knelt down and helpedthe boy 3 the things. 4 they were going the same way, he offered to carry some things for the boy. Asthey walked, Mark discovered 5 name was Bill. He loved video games, baseball and history, but he was having trouble with some of his 6 . They arrived at Bill's home first. Mark 7 in for a Coke and to watch some television. The afternoon 8 pleasantly with some laughs and small talk. Then Mark went home. They continued to see each other around school, had lunch together once or twice, then 9 graduatedfrom junior high school. They ended up in the same high school. Finally the long-awaited senior year came. Three weeks before graduation, Bill asked Mark if they could talk. Bill reminded him of the day years ago when they 10 . "Did you ever wonder 11 I was carrying so many things home that day?" asked Bill. "You see, I cleaned out my locker because I didn't want to leave a mess for 12 . I had stored away some of my mother's sleeping pills. I was going home to kill 13 . But after we spent some time together 14 and laughing, I realized that if I had died, I would have missed so many good times. So you see, Mark, when youpicked up those books that day, you did 15 . You saved my life." ( )1. A. walks ( )2. A. along with ( )3. A. picking up ( )4. A. Since ( )5. A. he ( )6. A. subject ( )7. A. was inviting ( )8. A. past ( ) 9. A. they both ( )10. A. had first met( )11. A. why ( )12. A. no one ( )13. A. me ( )14. A. talking ( )15. A. lots of B. was walking B. along B. picked up B. Because of B. the boy B. subjects B. invited B. pasted B. both of theyB. were meeting B. when B. everyone B. I B. to talk B. many more C. walked C. along and C. pick up C. Before C. her C. lesson C. was invited C. passed C. them both C. would meet C. where C. anyone else C. myself C. talk C. a lot of D. walking D. together D. to pick D. After D. the boy's D. class D. had invited D. pass by D. all of them D. met first D. that D. someone else D. my D. talked D. a lot more 查看答案
题型：单项选择题 用水清洗一堆蔬菜上残留的农药，用x单位量的水清洗一次以后，蔬菜上残留的农药量与本次清洗前残留的农药量之比为函数f（x）．设f（x）=11+x2，现有2单位量的水．方案（1）：一次清洗蔬菜；方案（2）：把水平均分成2份后清洗两次．则用方案（1）清洗后蔬菜上残留的农药量与用方案（2）清洗后蔬菜上残留的农药量之比______． 查看答案
题型：单项选择题 用显微镜观察细胞时，应选择下列哪种目镜和物镜的组合在视野内所看到的细胞数目最多（）A.目镜10×，物镜4×B.目镜10×，物镜10×C.目镜10×，物镜20×D.目镜10×，物镜40×E.目镜15×，物镜40× 查看答案