ChaseDream
搜索
返回列表 发新帖
00:00:00

It is theoretically possible that bacteria developed on Mars early in its history and that some were carried to Earth by a meteorite. However, strains of bacteria from different planets would probably have substantial differences in protein structure that would persist over time, and no two bacterial strains on Earth are different enough to have arisen on different planets. So, even if bacteria did arrive on Earth from Mars, they must have died out.

The argument is most vulnerable to which of the following criticisms?

正确答案: D

更多相关帖子

524

帖子

15

好友

4712

积分

ChaseDream

注册时间
2003-03-17
精华
8
解析
查看: 1961|回复: 1
打印 上一主题 下一主题

gwd1-8

[复制链接]
楼主
发表于 2008-4-19 20:33:00 | 只看该作者

gwd1-8

It is theoretically possible that bacteria developed on Mars early in its history and that some were carried to Earth by a meteorite.  However, strains of bacteria from different planets would probably have substantial differences in protein structure that would persist over time, and no two bacterial strains on Earth are different enough to have arisen on different planets.  So, even if bacteria did arrive on Earth from Mars, they must have died out.

The argument is most vulnerable to which of the following criticisms?

 

 

A.      It fails to establish whether bacteria actually developed on Mars.

B.      It fails to establish how likely it is that Martian bacteria were transported to Earth.

C.      It fails to consider whether there were means other than meteorites by which Martian bacteria could have been carried to Earth.

D.      It fails to consider whether all bacteria now on Earth could have arisen from transported Martian bacteria.

E.       It fails to consider whether there could have been strains of bacteria that originated on Earth and later died out.

我选c

why the answer is D?who can tell me the reason

沙发
发表于 2008-4-20 19:53:00 | 只看该作者

c是无关选项,因为即使不是meteorites带来的,Martian bacteria 也会遵循“两个星球的细菌在蛋白质结构上有本质不同”这个规律,不能weaken原文。

D是正确的,因为如果地球上的细菌全是Martian bacteria那么他们自然不会有本质的区别(本是同根生嘛),也就不能用这个标准判断他们是否土生土长于地球。

希望我说明白了

您需要登录后才可以回帖 登录 | 立即注册

Mark一下! 看一下! 顶楼主! 感谢分享! 快速回复:

手机版|ChaseDream|GMT+8, 2024-11-23 12:24
京公网安备11010202008513号 京ICP证101109号 京ICP备12012021号

ChaseDream 论坛

© 2003-2023 ChaseDream.com. All Rights Reserved.

返回顶部