扫描二维码，直接登录
题库 / Prep2008E1-CR-69
Which of the following most logically completes the reasoning?
When species are extensively hunted, individuals that reach reproductive maturity early make up a larger proportion of the population, because they have a better chance of reproducing. When species face diminished food resources, on the other hand, individuals tend to take longer to reach reproductive maturity. These considerations may help settle whether the primary cause of the gradual disappearance of North America's mastodons, prehistoric animals related to elephants, was diminished food resources or human hunting, since __________.
from the location of certain hunting weapons in juxtaposition with mastodon remains, it is possible to determine whether those weapons were used to hunt mastodons
the average age at which mastodons reached reproductive maturity can be established from mastodon tusks, of which there are many fossils dating from different periods
from the remains of mastodons already discovered, it can be accurately estimated when mastodons became extinct
from tusks and other bones, it is possible to determine whether male and female mastodons reached reproductive maturity at about the same age
it is possible to determine whether the earliest human dwellings constructed from mastodon tusks and bones come from an earlier period than the earliest hunting weapons unambiguously associated with mastodon remains
情景：由于不同原因，生物达到性成熟的年龄是不同的。若是被捕猎严重，则性成熟的年龄比较早；若是忍饥挨饿，则性成熟的年龄比较晚。
推理：题目其实要求我们依照给出的性成熟年龄不同，进而判断大象的灭绝原因。
选项分析：
A选项：从乳齿象化石周围的武器来看，有可能可以确定这些武器是不是用来猎杀乳齿象的。无论mastodon被什么东西所杀，都不是其性成熟的特点。
B选项：Correct. 乳齿象达到性成熟平均年龄是可以根据它的长牙来看出来的。若我们可以有一种方法判断乳齿象的性成熟年龄，那么由于性成熟年龄和遭遇事件的对应性，自然可以找到mastodon的灭绝原因。
C选项：从乳齿象的化石可以精确的知道它们是什么时候灭绝的。我们并不关心mastodon是什么时候灭绝的，而是灭绝时性成熟的年龄状况。
D选项：从长牙和其他的乳齿象的骨骼中是有可能确定雄性乳齿象和雌性乳齿象是否在同一时间达到性成熟的年龄的。我们想知道的是灭亡时的性成熟的情况，而不是公母之间的差异。
E选项：最早用乳齿象的长牙和骨头所建造的人类的住所的时间是否早于最早捕猎器具和乳齿象残骸建立确定关系。本选项描述的是mastodon的特点，不是性成熟的情况。
这题有一步比较tricky的链接：原文说hunting/food影响性成熟，而后面题干前却只提了hunting/food，容易让人遗忘性成熟和灭绝的关系
根据性成熟的时间来判断到底是哪一种解释更合理：性成熟早是因为人类捕杀，性成熟晚是因为食物缺乏
性成熟的年龄可以判断其是否是由于人工捕猎或缺乏食物，------可以判断它们的性成熟年纪即可
看清题目：was diminished food resources or human hunting 我们并不关心mastodon是什么时候灭绝的，而是灭绝时性成熟的年龄状况。
要知道的是灭亡时的性成熟的情况！’