In the embryonic stage of the industry life cycle, a company's investment needs and production costs are low.

The most versatile ______ embryonic stem cells, which ______ found in the embryo at the earliest stage of development and can grow into any part of the body.

A．are, are

B．is, is

C．are, is

D．is, are

The most versatile ______ embryonic stem cells, which ______ found in the embryo at the earliest stage of development and can grow into any part of the body.

A．are, are

B．is, is

C．are, is

D．is, are

The most versatile ______ embryonic stem cells, which ______ found in the embryo at the earliest stage of development and can grow into any part of the body.

A．are, are

B．is, is

C．are, is

D．is, are

Which of the following hypothetical scientific discoveries, if made, would weaken the author's arguments concerning the ethical risks of human cloning?

A．Through careful and documented study, cloning proves to be less risky than consanguineous breeding.

B．A laboratory process for reducing the number of stages in the cell division process is developed.

C．A non-cloning method for curing human fertility is discovered, thereby reducing the need to rely upon cloning.

D．A procedure for easing the acclimation of a foreign nucleus in the embryonic host is established.

E．A means of assessing genetic mistakes in a foreign nucleus before its implementation into a clone is devised.

Which of the following hypothetical scientific discoveries, if made, would weaken the author's arguments concerning the ethical risks of human cloning?

A．Through careful and documented study, cloning proves to be less risky than consanguineous breeding.

B．A laboratory process for reducing the number of stages in the cell division process is developed.

C．A non-cloning method for curing human fertility is discovered, thereby reducing the need to rely upon cloning.

D．A procedure for easing the acclimation of a foreign nucleus in the embryonic host is established.

E．A means of assessing genetic mistakes in a foreign nucleus before its implementation into a clone is devised.

Which of the following hypothetical scientific discoveries, if made, would weaken the author's arguments concerning the ethical risks of human cloning?

A．Through careful and documented study, cloning proves to be less risky than consanguineous breeding.

B．A laboratory process for reducing the number of stages in the cell division process is developed.

C．A non-cloning method for curing human fertility is discovered, thereby reducing the need to rely upon cloning.

D．A procedure for easing the acclimation of a foreign nucleus in the embryonic host is established.

E．A means of assessing genetic mistakes in a foreign nucleus before its implementation into a clone is devised.

An ethics crisis at one of the world's most successful human embryonic stem cell laboratories has plunged the controversial field of research into a new swirl of uncertainty. The accusations surrounding Korean cloning expert Woo Suk Hwang of Seoul National University--the first scientist to grow stem cells inside cloned human embryos--has already killed a spate of planned studies that sought to prove the cells' medical potential. The claims that Hwang may have obtained human eggs for his studies from women who felt pressured to donate are also reigniting a long-smoldering debate in the United States over the ethics of paying young women for their eggs, which are difficult to obtain but essential to the production of stem cells tailored to individuals.

Egg donation, which is generally safe but occasionally leads to serious and even life-threatening complications, has been a wedge issue in the stem cell debates, linking feminists and other liberal thinkers to conservatives who favor tighter limits on stem cell research. "We're in danger of making women into guinea pigs for this research even before there are any treatments to be tested," said Marcy Darnovsky, associate director of the Center for Genetics and Society in Oakland, Calif. "We really need clear rules that someone is enforcing."

With current techniques, it takes dozens of eggs to make a single cloned human embryo, which is destroyed in the process of extracting the stem cells. That means that if the field of therapeutic cloning is to advance--a field involving the creation of cloned embryos as sources of stem cells that would be genetically matched to particular patients--a significant number of eggs will be needed both to fuel the initial research and eventually to satisfy the demands of patients. Scientists at Advanced Cell Technology of Worcester, Mass. , made the decision to pay women only after a long analysis by an ethics board created by the company, said scientific director Robert Lanza. He still thinks it is the right way to go, Lanza said, given the painful injections involved, the uncomfortable egg suction procedure, and the approximately 5 percent chance of a serious case of hormonal over-stimulation, which can require hospitalization. Others say such payments cannot help but be coercive, especially for poor women who might feel compelled to take on those risks just to make ends meet. In April, the National Academies, chartered by Congress to advise the nation on matters of science, released a report that recommended against payments for human eggs beyond expenses incurred by the donors, in part because of the "sensitivities" inherent in the creation of embryos destined for destruction. But the report's impact remains uncertain as research institutions, fertility clinics and the biggest wild card of them all--Congress--mull the Academies' findings.

What can we learn from the opening paragraph?

A．Hwang paid the women for their eggs in his studies.

B．The charge of Hwang re-activized the debate in U. S..

C．The debate in U. S. is about whether or not pay for eggs.

D．The planned studies will continue without interruption.

According to the passage, when biologists believed that the cells in the early embryo were undetermined, they made which of the following mistakes?

A．They did not attempt to replicate the original experiment of separating an embryo into two parts.

B．They did not realize that there was a connection between the issue of cell determination and the outcome of the separation experiment.

C．They assumed that the results of experiments on embryos did not depend on the particular animal species used for such experiments.

D．They assumed that it was crucial to perform. the separation experiment at an early stage in the embryo’s life.

E．They assumed that different ways of separating an embryo into two parts would be equivalent as far as the fate of the two parts was concerned.

A、entry barriers are high.

B、a company's business model is based on using its technology to innovate new kinds of products for related markets.

C、it needs to move fast to establish a presence in an industry, commonly an embryonic or growth industry.

D、the company must make the huge investment necessary to develop the set of value-chain activities required to make and sell products in the new industry.

One reason why a sheep, a less well-understood experimental subject than

the laboratory mouse, should have proved easier to clone may stem from

differences in the initial stages of the two species' embryonic development.

After reaching maturity in the ovary of the mother, the unfertilized eggs of all

(5) mammals accumulate a supply of proteins, and the means of producing fresh

protein. In this way, the mammalian egg brings with it a larder for the embryo

to make use of until its own genes activate and supply this requirement

themselves. The sheep embryo disposes of its store properly and need not

depend on its own genes until the sixteen-cell stage, four cell divisions

(10) successive to fertilization, while in contrast, the mouse embryo commences this

process more precociously, becoming reliant on the activity of its own genes

after just the first division when the fertilized egg becomes two cells.

Therefore, a foreign nucleus introduced into a sheep egg exploits a respite in its

host's biological development, allowing it to adapt to its new role before

(15) assuming genetic control.

Concomitantly, a nucleus introduced into a mouse egg must acclimatize

quickly for its genes to be able to direct embryonic development within a single

cell division, so perhaps there is insufficient time for the extensive re-

programming of compulsory gene activity. The human embryo is thought to rely

(20) on its own genes after three cellular divisions, which might or might not

provide time enough for a foreign nucleus to acclimate. However, were

scientists to comprehend the nature of the indispensable re-programming then

there is every likelihood that both mice and humans could be cloned.

Despite the long-standing availability of this technology, there has until

(25) recently been little interest in it. Some people suffering from infertility as a

result of rare hereditary diseases could produce offspring, but cloned individuals

may be at risk given scientists' limited knowledge of the long term effects of

allowing an "old" adult cell nucleus to commence life again in an egg. The

nucleus of a skin cell could have accumulated a multitude of genetic mistakes of

(30) no consequence to its role in the skin, but the same cell could prove deleterious

in other tissues, or immensely increase the probability of the affliction with

cancer. The threat to general human health posed by cloning, as opposed to the

individual, is difficult to determine, but the risks are almost certainly lower

than those encountered in the effective inbreeding of consanguine marriages,

(35) and thus there are no scientific grounds per se for banning cloning. Like other

practices inconsequential to the physical well being of humanity, but generally

deemed undesirable on moral or social grounds, the prohibition of human

cloning will ultimately rest with only a simple pragmatic decision.

In this passage, the author is primarily concerned with

A．advancing an argument against human cloning based on evidence from cloning experiments performed on lower life forms

B．measuring the technical and ethical limitations of the embryonic cloning process in mammals

C．refuting arguments against human cloning through the use of hard scientific evidence

D．illuminating the critical ethical distinctions in process between human cloning and sheep cloning

E．describing how the ethical issues in the quest for human cloning have given rise to new models of embryonic development