题干

组织是由细胞构成的,组织形成的过程大致是(  )

A:细胞分裂→细胞分化→细胞生长

B:细胞生长→细胞分化→细胞分裂

C:细胞分化→细胞分裂→细胞生长

D:细胞分裂→细胞生长→细胞分化

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答案(点此获取答案解析)

D

同类题4

阅读理解

    In her new book, “The Smartest Kids in the World,” Amanda Ripley, an investigative journalist, tells the story of Tom, a high-school student from Gettysburg, Pennsylvania, who decides to spend his senior year in Warsaw, Poland. Poland is a surprising educational success story: in the past decade, the country raised students' test scores from significantly below average to well above it. Polish kids have now outscored(超过……分数) American kids in math and science, even though Poland spends, on average, less than half as much per student as the United States does. One of the most striking differences between the high school Tom attended in Gettysburg and the one he ends up at in Warsaw is that the latter has no football team, or, for that matter, teams of any kind.

    That American high schools waste more time and money on sports than on math is an old complaint. This is not a matter of how any given student who plays sports does in school, but of the culture and its priorities. This December, when the latest Program for International Student Assessment (PISA) results are announced, it's safe to predict that American high-school students will once again display their limited skills in math and reading, outscored not just by students in Poland but also by students in places like South Korea, Belgium, the Netherlands, Finland, Singapore, and Japan. Meanwhile, they will have played some very exciting football games, which will have been breathlessly written up in their hometown papers.

    Why does this situation continue? Well, for one thing, kids like it. And for another, according to Ripley, parents seem to like the arrangement, too. She describes a tour she took of a school in Washington D.C., which costs thirty thousand dollars a year. The tour leader—a mother with three children in the school—was asked about the school's flaws(瑕疵). When she said that the math program was weak, none of the parents taking the tour reacted. When she said that the football program was weak, the parents suddenly became concerned. “Really?” one of them asked worriedly, “What do you mean?”

    One of the ironies(讽刺) of the situation is that sports reveal what is possible. American kids' performance on the field shows just how well they can do when expectations are high. It's too bad that their test scores show the same thing.

同类题5

阅读下列材料:

为落实开展社会大课堂活动,七年级(3)班李老师准备周六组织本班学生参观北京科技馆,要求学生周六早9:00准时在科技馆门前集合,然后几种买票参观.

小强家离北京科技馆4公里,周六他准备乘出租车去,为了解北京出租车的计价方式,小强周五晚上在网上查到了现行北京市出租车价格标准:

收费项目

收费标准

3公里以内收费

13元

基本单价

2.3元/公里

低速行驶和等候费

根据乘客要求停车等候或由于道路条件限制,时速低于12公里时,每5分钟早晚高峰期间加收2公里租价(不含空驶费)其他时间段加收1公里租价(不含空驶费)

预约叫车服务费

提前4小时以上预约每次6元,4小时以内预约每次5元

空驶费

单程旅客行驶超过15公里部分,基本单价加收50%的费用,往返载客(即起点和终点在2公里(含)范围以内)不加收空驶费

夜间收费

23:00(含)至次日5:00(不含)运营时,基本单价加收20%的费用

合乘收费

合乘里程部分,按非合乘情况下应付金额的60%付费

燃油附加费

1元/运次

备注:1、早高峰7:00(含)﹣﹣9:00(不含);晚高峰17:00(含)﹣﹣19:00(不含).

      2、出租车计价段里程精确到500米,时间精确到2.5分钟;出租汽车收费结算以元为单位,元以下四舍五入.

      3、过路、过桥费由乘客负担.

      4、按日结算的包车及出北京行政区域的客运业务收费实行市场调节价.

在仔细阅读标准后,小强准备周六早上8点10分乘车,路上留出10分钟出租车时速低于12公里的堵车时间,这样在9点之前一定能顺利到达科技馆.时间设计好后,经过计算小强向妈妈要30元打车钱,妈妈问他30元钱够吗?小强说:“我按上表计算了,30元钱还有几块钱的剩余呢.”

下面是小强的分析与计算过程,请补充完整: