手機APP下載

您現在的位置: 首頁 > SAT > SAT每日一題 > 正文

SAT官方每日一題附答案和解析[閱讀](2019年12月30日)

來源:可可英語 編輯:max ?  VIP免費外教試聽課 |  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官方每日一題附答案和解析[閱讀](2019年12月30日)

The lines on the graph represent the 3-year running average of the southern sea otter population in the north, central, and south coastal regions.

Adapted from Brian Hatfield and Tim Tinker, "Spring 2015 California Sea Otter (Enhydra lutris nereis) Census Results." Published in 2015 by US Geological Survey.

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.

重點單詞   查看全部解釋    
range [reindʒ]

想一想再看

n. 范圍,行列,射程,山脈,一系列
v. 排

 
population [.pɔpju'leiʃən]

想一想再看

n. 人口 ,(全體)居民,人數

聯想記憶
unexpected ['ʌnik'spektid]

想一想再看

adj. 想不到的,意外的

 
approximately [ə'prɔksimitli]

想一想再看

adv. 近似地,大約

 
calculated ['kælkjuleitid]

想一想再看

adj. 計算出的;適合的;有計劃的 v. 計算;估計;

 
overall [əuvə'rɔ:l]

想一想再看

adj. 全部的,全體的,一切在內的
adv.

 
boom [bu:m]

想一想再看

n. 繁榮,低沉聲,帆杠,水柵
vi. 急速增

聯想記憶
affected [ə'fektid]

想一想再看

adj. 受影響的,受感動的,受疾病侵襲的 adj. 做

聯想記憶
critical ['kritikəl]

想一想再看

adj. 批評的,決定性的,危險的,挑剔的
a

 
decline [di'klain]

想一想再看

n. 衰微,跌落; 晚年
v. 降低,婉謝

 
?
發布評論我來說2句

    最新文章

    可可英語官方微信(微信號:ikekenet)

    每天向大家推送短小精悍的英語學習資料.

    添加方式1.掃描上方可可官方微信二維碼。
    添加方式2.搜索微信號ikekenet添加即可。
    这期福彩开奖号码 组选包胆选号技巧 北京11选五中奖规则 河北快三是正规的吗 最好的股票配资平台 2020重庆欢乐生肖 全国前10正规配资公司 加拿大卑诗快乐8算法 河内一分彩平台玩法技巧 2011年12月上证指数 黑龙江6加1开奖结果查询