首页
登录
职称英语
Birds are warm-blooded, vertebrate animals whose bodies are covered with fea
Birds are warm-blooded, vertebrate animals whose bodies are covered with fea
游客
2023-09-25
36
管理
问题
Birds are warm-blooded, vertebrate animals whose bodies are covered with feathers. Other characteristics of birds are: wings; a short tail bone; the visible tail being composed entirely of feathers; a weak or nonexistent sense of smell; no teeth; and keen hearing, despite the absence of external ears. As in mammals (哺乳动物), the only other group of warm-blooded animals, the blood in the veins (静脉) of birds is kept totally separated from the blood in the arteries(动脉).
Birds evolved from reptiles, especially from some small dinosaur-relative. Gradually the scales of the dinosaur evolved into feathers, perhaps first for insulation as the animal evolved from cord to wing blade but later for flight. It is still unknown, however, whether flight developed when a ground-living form began to flap its wings to increase its running speed (like the ostrich today), or when a tree climbing form used imperfect wings to aid it in leaping from tree limb to tree limb. The evolution from reptile to the bird as we know it concluded about 75 million years ago, at the beginning of the Tertiary period, or age of mammals.
The earliest classification of birds relied upon easily recognized external characteristics or upon peculiarities of behavior or appearance. For example, all web-footed birds were grouped together and all seed-eating birds were grouped together. Since the 19th century and the general acceptance of evolution, however, this method has given way to a sounder and more scientific procedure. Birds, as well as all other living things, are now classified in a way that best expresses their blood relationships and lines of descent. This kind of classification is known as a phylogenetic classification(系谱分类).
选项
A、piece of science fiction (科幻小说)
B、lecture
C、romantic story
D、news story
答案
B
解析
本题考察对文章文体的把握。这是一篇关于鸟类的文章,作者用客观、科学的语言向我们讲述了鸟类的特征、进化和分类。文中大量专业术语表明它节选自学术类讲座,因此选B。
转载请注明原文地址:https://tihaiku.com/zcyy/3043763.html
相关试题推荐
Accordingtothepassage,scientistshavediscoveredthatinfluenzaviruses____
Accordingtothepassage,scientistshavediscoveredthatinfluenzaviruses____
Accordingtothepassage,scientistshavediscoveredthatinfluenzaviruses____
Two-thirdsoftheearth’ssurface(be)______coveredwithwater.is
Humanbeingsare(create)______animals.creative形容词作animals的定语。
Nothavingbeendiscovered,manylawsofnatureactuallyexistinnature.A、虽然自然界
Someanimals______wellenoughinthatcountry.A、havenotprotectedB、isnotbe
Scientiststhinkthedifferencebetweenanimalsandmenis______.[br]Now,sci
Scientiststhinkthedifferencebetweenanimalsandmenis______.[br]Thepass
Scientiststhinkthedifferencebetweenanimalsandmenis______.[br]Thepass
随机试题
Embracingfailureisaclicheofthebusinessworld.ButasMatthewSyed,aj
Whatarethetwopeopletalkingaboutinthisconversation?[originaltext]M:Let
Icanjump(far)______thanTom.farther空白处后面是一个表示比较级的than,所以前面应该用副词far的比较级,故正确答
Determinewhatnumbershouldreplacethequestionmark:164243256
BI(BusinessIntelligence)是通过运用基于事实的支持系统来
某患者,颈后疮形高肿,色红,多个脓头,焮热剧痛。伴发热,口渴,尿赤,舌红苔黄,脉
A.地高辛B.洋地黄毒苷C.乙胺丁醇D.异烟肼E.呋塞米可诱使肝炎患者发生肝昏迷
从根本上说,教师的教育威信来自于()。 A.教师高尚的教育人格B.社会尊师
2006-17.瞳孔散大多属 A.肝风内动B.肝经风热C.气血不足D.肾
便秘的伴随症状
最新回复
(
0
)