![](https://lstatic.shangxueba.com/jiandati/h5/images/m_q_title.png)
Many experts remain skepticalabout his claimsA.untouched B.certainC.dou
Many experts remain skepticalabout his claims
A.untouched
B.certain
C.doubtful
D.silent
Many experts remain skepticalabout his claims
A.untouched
B.certain
C.doubtful
D.silent
DNA is the genetic material found within the cell nuclei of all livingthings. In mammals(哺乳动物)the strands of DNA are grouped into structures called chromosomes(染色体). With the exceptionof identical twins, the complete DNA of each individual is unique.
DNA fingerprinting is sometimes called DNAtyping. It is a method of identification that compares bits of DNA. A DNAfingerprint is constructed by first drawing out a DNA sample from body tissueor fluid such as hair, blood, or saliva(唾液). The sample is then segmented using enzymesc酶) , and the segmentsare arranged by size. The segments are marked with probes and exposed on X-rayfilm,where they form. a pattern of black bars-the DNA fingerprint. If the DNAfingerprints produced from two different samples match, the two samplesprobably came from the same person.
DNA fingerprinting was firstdeveloped as an identification technique in 1985. Originally used to detect thepresence of genetic diseases, it soon came to be used in criminalinvestigations and legal af-fairs. The first criminal conviction based on DNAevidence in theUnited Statesoccurred in 1988. In criminalinvestigations, DNA fingerprints derived from evidence collected at the crimescene are com-pared to the DNA fingerprints of suspects. Generally, courts haveaccepted the reliability of DNA tes-ting and admitted DNA test results intoevidence. However, DNA fingerprinting is controversial in a number of areas:the accuracy of the results, the cost of testing, and the possible misuse of thetech-nique.
The accuracy of DNAfingerprinting has been challenged for several reasons. First, because DNAsegments rather than complete DNA strands are "fingerprinted"; a DNAfingerprint may not be unique; large-scale research to confirm the uniquenessof DNA fingerprinting test results has not been conducted. In addition, DNAfingerprinting is often done in private Iaboratories that may not followuniform. testing standards and quality controls. Also, since human beings mustinterpret the test, human error could lead to false results.
DNA fingerprinting isexpensive. Suspects who are unable to provide their own DNA to experts may notbe able to successfully defend themselves against charges based on DNAevidence.
Widespread use of DNA testingfor identification purposes may lead to the establishment of a DNA fingerprintdatabase.
If two sisters are identical twins, their complete DNAs are
A.the same
B.unique
C.different
D.similar
German researchers have comeup with a new generation of defibrillators(除颤器) and early-warn-ing software aimed at offeringheart patients greater _(51) from sudden death from cardiac ar-rest (心脏停搏).
InGermanyalone, around 100,000people die annually _(52) a result of cardiac arrest and many of these casesare caused by disruption to the heart's thythm. Those most at _(53) are patients who have alreadysuffered a heart attack, and for years the use of defibrillators has proved'useful in _ _(54)life-threatening disruptions to heart thythms and correcting them automaticallyby intervening within seconds. These devices _(55) on a range of functions, such asthat of pacemaker(起搏器).
Heart specialists atFreiburg's University Clinic have now achieved a breakthrough with anim-planted defibrillator (56) of generating a six-channelelectrocardiogram (ECG,心电图 ) with-in the body. This integrated systemallows _ _(57) diagnosis ofsevere blood-flow problems and a pending. (即将发生的) heartattack. It will be implanted in . _(58) for the first time this year.Meanwhile,researchers at the Fraunhofer Institute for Applied Mathematics inKaiserslautern have developed new computer software that _(59) the evalution ofECG data more precise.
Theoverwhelming majority of patients at risk will not have an implanteddefibrillator and must for this _(60)undergo regular ECGs. "Many of the current programs only take into _ (61) a linear correlation of the data.We are, however, making use of a non-linear process (62) reveals the chaotic patterns ofheart beats as an open and complex system," Hagen Knaf says,"In thisway changes in the heart _(63) over time can be monitored and individualvariations in patients taken into account. " An old study of ECG data,based upon 600 patients who had (64)a subsequent heart attack, enabled the researchers to compare risks and to showthat the new software evaluates the (65) considerably better.
A.service
B.discount
C.protection
D.advice
A.To make its population grow
B.To keep it separate from the world
C.To encourage its people to get rich
D.To keep its tradition and customs
A.Other scientists are now searching for evidence to prove this
B. A Swiss writer named Erich Von Daniken wrote that the Nazca lines were designed as a landing place for UFOs
C.Scholars differ in interpreting the purpose of the designs.
D.The largest pictures may have been the sites for special ceremomes
E.Seen from the ground, it looks like lines scratched into the earth
F.He called Nazca "the largest astronomy book in the world"
为了保护您的账号安全,请在“简答题”公众号进行验证,点击“官网服务”-“账号验证”后输入验证码“”完成验证,验证成功后方可继续查看答案!