手机APP下载

您现在的位置: 首页 > SAT > SAT每日一题 > 正文

SAT官方每日一题附答案和解析[阅读](2017年9月14日)

来源:可可英语 编辑:max   可可英语APP下载 |  可可官方微信:ikekenet


Critical Reading>Select an Answer

The recovery of southern sea otters appears to have taken an upturn, according to results from the annual California sea otter survey released by the U.S. Geological Survey. Yet despite an overall increase in sea otter abundance, sharks have been "taking a bite" out of the portion of the population that could fuel expansion into new areas.

"There's much more to the story here than the main finding would suggest," said Dr. Tim Tinker, a research ecologist who leads the USGS sea otter research program. "We are looking into various factors that may be affecting the survey results, including a boom in urchin abundance from Big Sur to Monterey that may explain the uptick in numbers in the range center, and high levels of shark bite mortality that are likely responsible for continued declines at the north and south ends of the range."

This year's survey results suggest an increasing trend over the last five years of almost 2 percent per year and the population index, a statistical representation of the entire population calculated as the three-year running average of census counts, has climbed to 3,054 from 2,711 in 2010. The growth is accounted for by an unexpected jump in numbers in the center of the sea otter's range, an area that spans from Monterey south to Cambria.

While the population index continues to trend upward, the northern and southern subsets of the population continue a five-year decline, dropping 2 percent and 3.4 percent per year, respectively, numbers consistent with increased shark bite induced mortality in these same areas.

Since the 1980s, USGS scientists have computed the annual population index and evaluated trends in the southern sea otter, "Enhydra lutris nereis," a federally listed threatened species found in California. For southern sea otters to be considered for removal from threatened species listing under the Endangered Species Act, the population index would have to exceed 3,090 for three consecutive years.

SAT官方每日一题附答案和解析[阅读](2017年9月5日)

Based on the passage and the graph, what can reasonably be inferred about predatory shark activity in the south region?

A.It steadily decreased between 2000 and 2003.
B.It affected otters at a consistent rate between 2003 and 2006.
C.It was more of a threat to sea otters in 2003 than in 2009.
D.It was at its highest level in 2009.

重点单词   查看全部解释    
ecologist [i:'kɔlədʒist]

想一想再看

n. 生态学家

 
abundance [ə'bʌndəns]

想一想再看

n. 丰富,充裕

联想记忆
statistical [stə'tistikəl]

想一想再看

adj. 统计的,统计学的

 
critical ['kritikəl]

想一想再看

adj. 批评的,决定性的,危险的,挑剔的
a

 
boom [bu:m]

想一想再看

n. 繁荣,低沉声,帆杠,水栅
vi. 急速增

联想记忆
range [reindʒ]

想一想再看

n. 范围,行列,射程,山脉,一系列
v. 排

 
mortality [mɔ:'tæliti]

想一想再看

n. 必死的命运,死亡数目,死亡率

联想记忆
shark [ʃɑ:k]

想一想再看

n. 鲨鱼
n. 贪婪的人,放高利贷的人,老手

 
survey [sə:'vei]

想一想再看

v. 调查,检查,测量,勘定,纵览,环视
n.

 
overall [əuvə'rɔ:l]

想一想再看

adj. 全部的,全体的,一切在内的
adv.

 

发布评论我来说2句

    最新文章

    可可英语官方微信(微信号:ikekenet)

    每天向大家推送短小精悍的英语学习资料.

    添加方式1.扫描上方可可官方微信二维码。
    添加方式2.搜索微信号ikekenet添加即可。