According to a theory advanced

by researcher Paul Martin, the wave

of species extinctions that occurred

Line in North America about 11,000 years

(5) ago, at the end of the Pleistocene era,

can be directly attributed to the arrival

of humans, i.e., the Paleoindians, who

were ancestors of modern Native

Americans. However, anthropologist

(10) Shepard Krech points out that large

animal species vanished even in areas

where there is no evidence to demon-

strate that Paleoindians hunted them.

Nor were extinctions confined to large

(15) animals: small animals, plants, and

insects disappeared, presumably not

all through human consumption. Krech

also contradicts Martin’s exclusion of

climatic change as an explanation by

(20) asserting that widespread climatic

change did indeed occur at the end of

the Pleistocene. Still, Krech attributes

secondary if not primary responsibility

for the extinctions to the Paleoindians,

(25) arguing that humans have produced

local extinctions elsewhere. But,

according to historian Richard White,

even the attribution of secondary

responsibility may not be supported

(30) by the evidence. White observes that

Martin’s thesis depends on coinciding

dates for the arrival of humans and the

decline of large animal species, and

Krech, though aware that the dates

(35) are controversial, does not challenge

them; yet recent archaeological

discoveries are providing evidence

that the date of human arrival was

much earlier than 11,000 years ago.

Q7:

Which of the following, if true, would most weaken Krech’s objections to Martin’s theory?

答案B

请问，这题中的C选项是否也有削弱的作用呢？如果在物种消失以前就有这种天气的变更，那“由天气变更引起物种灭绝”的假设就有问题了啊。我的想法有问题吗？

题目问的是weaken Krech’对Martin的反对。

K的观点是：contradicts Martin’s exclusion of climatic change as an explanation asserting that widespread climati change did indeed occur at the end of the Pleistocene.

也就是说M 认为climatic change did not occur .

K认为M不应该排除(exclusion )环境曾发生过巨大变化的可能性。所以B选项是加强而不是削弱K的观点