下列关于马进化过程的叙述中，符合达尔文学说的观点是（）
A、广阔草原对始祖马进行了定向选择
B、始祖马的不定向变异，是因为环境的改变
C、马趾产生的变异，都能适应环境条件的改变
D、始祖马趾的变化，是因为生活环境由灌木丛到广阔的草原
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下列关于马进化过程的叙述中，符合达尔文学说的观点是（）
A、广阔草原对始祖马进行了定向选择
B、始祖马的不定向变异，是因为环境的改变
C、马趾产生的变异，都能适应环境条件的改变
D、始祖马趾的变化，是因为生活环境由灌木丛到广阔的草原
Passage 2Several research teams have found that newborns prefer their mothers' voices over those of other people. Now a team of scientists has gone an intriguing step further: they have found that newborns cry in their native language."We have provided evidence that language begins with the very first cry melodies,"says Kathleen Wermke of the University of Wirzburg, Germany, who led the research."The dramatic finding of this study is that not only are newborns capable of producing different cry melodies, but they prefer to produce those melody patterns that are typical for the ambient language they have heard during their fetal life, within the last trimester,"said Wermke."Contraryto orthodox interpretations, these data support the importance of human infants' crying for seeding language development."It had been thought that babies' cries are constrained by their breathing patterns and respiratory apparatus, in which case a crying baby would sound like a crying baby no matter what the culture is, since babies are anatomically identical."The prevailing opinion used to be that newborns could not actively influence their production of sound,"says Wermke. This study refutes that claim: since babies cry in different languages, they must have some control(presumably unconscious) over what they sound like rather than being constrained by the acoustical properties of their lungs, throat, mouth, and larynx. If respiration alone dictated what a cry sounded like, all babies would cry with a falling-pitch pattern, since that's what happens as you run out of breath and air pressure on the throat's sound-making machinery decreases. French babies apparently didn't get that memo."German and French infants produce different types of cries, even though they share the same physiology,"the scientists point out."The French newborns produce ' nonphysiological' rising patterns,"showing that the sound of their cries is under their control.Although phonemes-speech sounds such as "ki"or"sh"-don't cross the abdominal barrier and reach the fetus, so-called prosodic characteristics of speech do. These are the variations in pitch, rhythm, and intensity that characterize each language. Just as newborns remember and prefer actualsongs that they heard in utero, it seems, so they remember and prefer both the sound of Mom's voice and the melodic signature of her language.The idea of the study wasn't to make the sound of a screaming baby more interesting to listeners-good luck with that-but to explore how babies acquire speech. That acquisition, it is now clear, begins months before birth, probably in the third trimester. Newborns "not only have memorized the main intonation patterns of their respective surrounding language but are also able to reproduce these patterns in their own [ sound] production,"conclude the scientists. Newborns'"cries are already tuned toward their native language", giving them a head start on sounding French or German (or, presumably, English or American or Chinese or anything else: the scientists are collecting cries from more languages). This is likely part of the explanation for how babies develop spoken language quickly and seemingly without effort. Sure, we may come into the world wired for language(thank you, Noam Chomsky), but we also benefit from the environmental exposure that tells us which language.Until this study, scientists thought that babies became capable of vocal imitation no earlier than12 weeks of age. That's when infants listening to an adult speaker producing vowels can parrot the sound. But that's the beginning of true speech. It's sort of amazing that it took this long for scientists to realize that if they want to see what sounds babies can perceive, remember, and play back, they should look at the sound babies produce best. So let the little angel cry: she's practicing to acquire language.When does language acquisition begin according to the research?
A、It begins with the birth of a baby.
B、It begins before the birth of a baby.
C、It begins when a
请指出该文存在的主要问题，并提出修改意见。
某转录下来的mRNA的碱基中U占16％、A占20％，则模板DNA中G占（）
A、36％
B、32％
C、64％
D、无法确定
元代学识深厚的少数民族画家是（）。
A、钱选
B、李衍
C、高克恭
D、王渊
山水画作《雪景寒林图》的作者是（）。
A、范宽
B、李成
C、马远
D、徐渭
