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?
V3甲烷那篇,还有题问suggest what of the sendiments in the sea? 还有题问忘了是文中提到的植被的减少还是增加的后果(反正是导致产生了很多甲烷),我选的是end of ice age(仅供参考,需要考时看清题目具体分析)(760)
v4:
1P说甲烷和二氧化碳一样是一种温室气体;也会造成global warming。列举了造成大气中M物质增加的塬因,如燃烧石化燃料等。fuel fossil burn, fire and other.(有题考这段的作用,我认为是提供背景资料)
2P “Surprisingly”(转折)科学家发现植物plant也会释放M,提出如卫星空照的证据,说热带地区因为有较密集的丛林tropical forest,所以大气中的M特别集中。The article listed two studys to demonstrate that the plants really emit the methane.
最近,我们从1995年诺贝尔奖得主克鲁琛(Paul J. Crutzen)等人那儿,得到了进一步的支持。我们的发现于2006年1月发表之后,他们重新分析了1988年由委内瑞拉莽塬的空气样本所测得的结果,并推断有3000~6000万公吨的甲烷,可能是由这些地区的植物所释放。克鲁琛说:「回头看1988年,我们早就应该发现了,只是我们固守成见,认为甲烷只能在厌氧的状态下生成,以致错失了良机。」
亲,你看这个
GWD6-Q40:
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.