题干

雄蛙的一个细胞经有丝分裂形成两个子细胞(S1,S2),一个初级精母细胞经减数第一次分裂形成两个次级精母细胞(C1,C2)。比较C1与C2,S1与S2细胞核中的DNA数目及其贮存的遗传信息,正确的是         (   )

A:DNA数目C1与C2相同,S1与S2不同

B:遗传信息C1与C2相同,S1与S2不同

C:DNA数目C1与C2不同,S1与S2相同

D:遗传信息C1与C2不同,S1与S2相同

上一题 下一题 0.0难度 选择题 更新时间:2017-07-03 12:35:49

答案(点此获取答案解析)

D

同类题3

阅读材料,完成下列要求。

材料一:儒学是中国传统文化的主干,是中国古代社会的主流意识形态。对中国国家的稳定和经济的发展提供了有利条件。可是,到了近代,儒学却连连遭到批判,其地位和影响不断削弱、衰微,最终失去主流、统治地位,被边缘化。这是中国儒学发展、演变史上的一个重要转折……儒学的衰微其实是中国近代社会变革、社会转型和文化革新、文化转型的必然结果。这一过程与中国近代化的展开、古代社会的解体基本同步,其历史必然性不言而喻。不同性质的社会变革一旦在中国展开,文化革新就相应提上了日程,就势必要不断触动传统儒学,以致最终否定它的神圣地位。在变革过程中,中国古代社会结构逐步解体,儒学也势必随之同步衰微。

——张锡勤《儒学在中国近代的命运》

材料二:韩国是一个善于学习的民族,……到了现代,他们一方面提倡世界化(实际是向美国看齐的现代化),另一方面又保护和弘扬以儒家文化为主体的中国传统文化。后者做得甚至比中国还好。从小到集体的人与人之间,大到国家的爱国主义精神支柱,每一步都渗透着儒家文化的传统素质。以儒家精神为基础的韩国人精神及其思维模式,还强调人在社会中的关系,“群体内的和谐”与“群体外的竞争”密切结合,使得韩国国内稳定不乱,又能在国际经济发展中大显身手,促使其综合国力名列前茅。

——《中国儒家传统文化对韩国社会发展的影响》

同类题4

阅读理解

    Gravity signals that race through the ground at the speed of light could help seismologists(地震学家) get a better handle on the size of large, destructive quakes soon after they hit,a study suggests. The tiny changes in Earth's gravitational field, created when the ground shifts, arrive at earthquake monitoring stations well before earthquake waves.

    “The good thing we can do with these signals is have quick information on the magnitude (震级) of the quake,” says Martin Vaillée, a seismologist at the Paris Institute of Earth Physics.

    Earthquake equipment in China and South Korea picked up gravity signals immediately after the magnitude-9. 1 Tohoku earthquake that destroyed parts of Japan in 2011. The signals appear as tiny accelerations on earthquake-recording equipment, more than a minute before the seismic waves show up.

    “We can look before the earthquake waves arrive,” says Vallée. “If we see nothing, we can say that the quake that made these was maybe large, but not huge. If we see the signals, it means we really have a very big quake. ”

    Had seismologists been monitoring for gravity changes, they might have realized sooner just how big the Tohoku earthquake was. A small increase in an earthquake's magnitude means a large change in the energy released by the quake-and the destruction expected. That information is important for emergency responders as they decide what resources to arrange.

    It'll be a major contribution if gravitational waves can beat down the time needed to know that a big earthquake is big. But much work remains before gravity signals can be considered a reliable tool in the vital minutes after a big quake. A few extra minutes of warning can save lives, particularly in coastal areas where people can flee ahead of an incoming tsunami.