题干

有关分类单位的叙述中,正确的是(  )


A:分类单位越小,所包含的种类越小

B:分类单位越小,植物所包含的共同特征越多

C:同一分类单位中,植物的特征是完全相同的

D:越小的分类单位,植物的种类越多

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答案(点此获取答案解析)

B

同类题4

阅读下列材料,回答问题。

材料一: “养老”在中国古代的礼制中有着重要的地位。据《礼记·王制》记载:“殷人养国老于右学,养庶老于左学;周人养国老于东胶,养庶老于虞庠。”汉代,统治者强调以孝道治理天下。《王杖诏书》中规定:70岁以上的老人,朝廷赐给手杖。凭此杖,老人可享受600.石俸禄的官吏待遇。同时在乡里设三老,选地方年长且德高望重者任职,负责教化地方,解决民间纠纷。唐宋以后,保持了由皇帝宴请老人的习俗,称为“观酺”。如康熙六十大寿时,举办“千叟宴”,宴请天下老人。同时在全社会旌表高寿老人,对于年过百岁者,“照例给予建坊银,赠‘升平人瑞’匾额”。

——摘编自刘松林《古代中国的养老制度》

材料二: 现代社会保障制度发源于德国。德国俾斯麦时期,分别于1883年、1884年、1889年颁布了疾病、工伤、老龄和伤残三项法案,建立了三项保险制度。这一立法颁布后,很快被其它国家纷纷效仿。西方各国的养老保险,既有政府强制实行的基本养老保险,也有企业实施的保险,以及个人自愿参加的商业保险。1935年,美国通过了《社会保险法》,养老保险覆盖了95%的工薪阶层。英国在二战后实施了全民保障、全面保障。英国居民个人一生中都要与社会保障制度发生或多或少的联系,国家强制所有在毕业离校年龄和退休年龄之间的公民参加养老保险。

——摘编自赵书博《西方国家养老保险制度研究及借鉴》

同类题5

阅读理解

    The more hours that young children spend in child care, the more likely they are to turn out aggressive and disobedient by the time they are in kindergarten, according to the largest study of child care and development ever conducted. Researchers said this correlation (相关性) held true regardless of whether the children came from rich or poor homes, were looked after by a relative or at a center, and whether they were girls or boys.

    What is uncertain, however, is whether the child care actually causes the problem or whether children likely to turn out aggressive happen to be those who spend more hours in child care. It also remains unclear whether reducing the amount of time in child care will reduce the risk that a child will turn into a mean person. What's more, quality child care is associated with increased skills in intellectual ability such as language and memory, leading some academics to suggest that child care turns out children who are “smart and naughty”.

    The government-sponsored research, which has tracked more than 1,300 children at 10 sites across the country since 1991, is bound to cause the debate over child care again: How should people balance work and family? And how should parents, especially mothers. Resolve the demands that are placed on them to be both breadwinners and supermoms?

    That debate was already on display at a news briefing yesterday, where researchers themselves had different opinions about the data and its implications (含义). “There is a constant relationship between time in care and problem behavior, especially those involving aggression and behavior,” said Jay Belsky of Birkbeck College in London, one of the lead investigators of the study who has previously annoyed women's groups because of his criticisms of child care. “On behalf of fathers or mothers?” interrupted Sarah Friedman, a developmental psychologist at the National Institute of Child Health and Human Development (NICHD) and one of the other lead scientists on the study. “On behalf of parents and families,” responded Belsky.

    “NICHD is not willing to get into policy recommendations.” said Friedman, contradicting her colleague. “There are other possibilities that can be entertained. Yes it is a quick solution—more hours in child care is associated with more problems. The easy solution is to cut the number of hours but that may have implications for the family that may not be beneficial for the development of the children in terms of economics.” In an interview after the briefing, Friedman said that asking parents to work fewer hours and spend more time with their children usually meant a loss of family income, which adversely(不利地) affects children.

    Scientists said that the study was highly reliable. But the researchers said they had no idea whether the behavioral difficulties persisted as the children moved to higher grades.