题干

2003年8月份《时事社》报道:日本的遗传学和免疫学家成功地将一种人工合成的能够控制合成人体某种免疫抗体的基因,插入了牛的染色体中,使人们从牛的血清和乳汁得到了相应的抗体。试想,科学家们是在这头牛的什么发育时期和细胞有丝分裂的什么时期,完成的转基因工作(   )

A:受精卵、中期

B:囊胚期、后期

C:原肠胚、间期

D:受精卵、间期

上一题 下一题 0.0难度 选择题 更新时间:2018-07-27 02:38:03

答案(点此获取答案解析)

D

同类题1

阅读理解

D

    The Intelligent Transport team at Newcastle University have turned an electric car into a mobile laboratory named “DriveLAB” in order to understand the challenges faced by older drivers and to discover where the key stress points are.

    Research shows that giving up driving is one of the key reasons for a fall in health and well-being among older people, leading to them becoming more isolated(隔绝) and inactive.

    Led by Professor Phil Blythe, the Newcastle team are developing in-vehicle technologies for older drivers which they hope could help them to continue driving into later life.

    These include custom-made navigation(导航) tools, night vision systems and intelligent speed adaptations. Phil Blythe explains: “For many older people, particularly those living alone or in the country, driving is important for preserving their independence, giving them the freedom to get out and about without having to rely on others.”

    “But we all have to accept that as we get older our reactions slow down and this often results in people avoiding any potentially challenging driving conditions and losing confidence in their driving skills. The result is that people stop driving before they really need to.”

    Dr Amy Guo, the leading researcher on the older driver study, explains, “The DriveLAB is helping us to understand what the key points and difficulties are for older drivers and how we might use technology to address these problems. “For example, most of us would expect older drivers always go slower than everyone else but surprisingly, we found that in 30mph zones they struggled to keep at a constant speed and so were more likely to break the speed limit and be at risk of getting fined. We're looking at the benefits of systems which control their speed as a way of preventing that.

    “We hope that our work will help with technological solutions(解决方案) to ensure that older drivers stay safer behind the wheel.”