4008-125-888
首页>ACT>ACT科学>ACT科学Session1生物(实战练习Practice 6)

ACT科学Session1生物(实战练习Practice 6)

2017-05-08 15:24来源:互联网作者:上海管理员

摘要:

  (61F-Passage I)

  Frog eggs develop into tadpoles, which then metamorphose into adult frogs. Recently, reported observations of frogs with morphological abnormalities (usually a missing or malformed hind limb) have increased in many localities. Four hypotheses attempt to explain this increase.

  Hypothesis 1假设1

  Tadpoles are commonly parasitized by trematodes, flatworms that burrow into the tadpoles, causing cysts to form. The presence of cysts during tadpole development can cause morphological abnormalities in the adult frog. Thus, increases in trematode populations most likely account for the recent increase in morphological abnormalities.

  Hypothesis 2假设2

  Due to industrial pollution, Earth’s ozone layer has thinned. This process has led to an increase in the amount of ultraviolet (UV) radiation reaching Earth’s surface. UV radiation can directly cause abnormalities in frog eggs by producing mutations in the DNA that controls frog development UV radiation can also indirectly cause abnormalities in frog eggs by chemically transforming certain pollutants into teratogens, chemicals that cause developmental abnormalities. Hypothesis 3假设3

  Certain pesticides contain a class of compounds called retinoids. Frogs naturally produce retinoids, but at high concentrations, retinoids cause mutations in frog eggs. These mutations later result in morphological abnormalities. Many of these mutations affect genes that control hind limb development. Thus, the recent increase in morphological abnormalities is probably due to an increase in retinoids from pesticides.

  Hypothesis 4假设4

  Tadpoles and frogs are prey for many aquatic predators, including fish, turtles, and wading birds such as herons. Predator attacks are not always completely successful; many result in injured frogs and tadpoles. Permanent injuries in tadpoles and frogs could later appear to be developmental abnormalities. Thus, increases in predator populations most likely account for the recent increase in morphological abnormalities.

  Practice 6.1

  Which 2 hypotheses argue that the recent increase in morphological abnormalities in frogs is the result of human activities?

  A. Hypotheses 1 and 4

  B. Hypotheses 2 and 3

  C. Hypotheses 2 and 4

  D. Hypotheses 3 and 4

  Practice 6.2

  All 4 hypotheses propose that the factors causing morphological abnormalities in frogs are present in the:

  F. pesticides used by farmers.

  G. environment in which the frogs live.

  H.UV radiation produced by the Sun.

  J. bodies of the organisms that prey on frogs.

  Practice 6.3

  Which 2 hypotheses propose that direct contact between tadpoles and another organism results in morphological abnormalities in frogs?

  A. Hypotheses 1 and 4

  B. Hypotheses 2 and 3

  C. Hypotheses 2 and 4

  D. Hypotheses 3 and 4

  Practice 6.4

  An artificial pond was created. The following were added to the pond: trematodes, UV-induced teratogens, retinoids, frog predators, tadpoles, and materials necessary for tadpole development. The frequency of morphological abnormalities in frogs was very high. This finding best supports which, if any, of the 4 hypotheses, and why?

  F. Hypothesis 1, since it shows that the morphological abnormalities are caused by parasitism by trematodes.

  G. Hypothesis 2, since it shows that the morphological abnormalities are the result of DNA mutations caused by teratogens.

  H. Hypothesis 3, since it shows that the morphological abnormalities are caused by the presence of retinoids.

  J. None of the 4 hypotheses is best supported, because the result does not indicate which factor caused the morphological abnormalities.

  Practice 6.5

  Normal adult frogs were captured, tagged, and released into a pond. After 2 months the frogs were recaptured and examined. Five percent of these frogs showed morphological abnormalities, such as missing hind limbs. These results best support which hypothesis?

  A. Hypothesis 1

  B. Hypothesis 2

  C. Hypothesis 3

  D. Hypothesis 4

  Practice 6.6

  Supporters of Hypothesis 4 would most likely argue that the frequency of morphological abnormalities in frogs would be lowest in which of the following types of aquatic communities?

  F. Those with fish, turtles, and wading birds

  G. Those with fish and turtles, but without wading birds

  H. Those with fish and wading birds, but without turtles.

  J. Those without fish, turtles, and wading birds

  Practice 6.7

  A biologist has argued that some of the factors cited in both Hypothesis 1 and Hypothesis 2 are combining to cause the increase in the morphological abnormalities in frogs. Which of the following findings about trematodes, if true, would best support this view?

  A. Trematodes are highly sensitive to injury from UV light

  B. Trematodes are immobilized by teratogens.

  C. Exposure to UV light increases trematode populations.

  D. Exposure to UV light improves frogs’ resistance to trematode parasitism.

  Answers for Practice 17-32: Practice 6 B G A J D J C

  上海新航道学校作为业内良心ACT培训机构 ,坚持“英语”的理念,注重学术研究,注重培养学生的学习能力。想成为下一个高分学员?赶紧来新航道报名ACT培训班 吧!

免费领取资料

免费领取最新剑桥雅思、TPO、SAT真题、百人留学备考群,名师答疑,助教监督,分享最新资讯,领取独家资料。

方法1:扫码添加新航道老师

微信号:shnc_2018

方法2:留下表单信息,老师会及时与您联系

热门课程

  • 走读班(6-8人)
  • 走读班(3-6人)
  • ACT一对一
课程名称 班级人数 课时 学费 报名
ACT强化托管班(6-8人,走读) 3-6人 64 ¥21800 在线咨询
ACT冲刺托管班(6-8人,走读) 3-6人 64 ¥11800 在线咨询
课程名称 班级人数 课时 学费 报名
课程名称 班级人数 课时 学费 报名
ACT一对一 1 按需定制 ¥980元 在线咨询

热门搜索:

免责声明
1、如转载本网原创文章,请表明出处;
2、本网转载媒体稿件旨在传播更多有益信息,并不代表同意该观点,本网不承担稿件侵权行为的连带责任;
3、如本网转载稿、资料分享涉及版权等问题,请作者见稿后速与新航道联系(电话:021-64380066),我们会第一时间删除。

  • 徐家汇校区
  • 人民广场校区
  • 浦东校区
  • 中山公园校区
  • 杨浦校区
  • 闵行校区
  • 松江校区
  • 封闭集训营
  • 地址:徐汇区裕德路126号

    乘车路线:地铁1、4号线上海体育馆、3号线9号线宜山路站、11号线上海游泳馆站

  • 地址:南京西路338号天安中心24楼

    乘车路线:地铁1、2、8号线人民广场站

  • 地址:浦东新区世纪大道1128号耀通科技大厦3楼(地铁2号线世纪大道站12号口出)

    乘车路线:地铁2、4、6号线世纪大道站

  • 地址:长宁路1158号 贝多芬广场 A座4楼414室

    乘车路线:乘车路线:地铁3、4号线中山公园站

  • 地址:杨浦区国宾路18号万达广场A座18楼

    乘车路线:地铁10号线五角场站

  • 地址:东川路1779-19号

    乘车路线:地铁5号线 东川路站4号口出

  • 地址:松江大学城四期校区:文汇路928弄想飞天地2204

    乘车路线:地铁9号线松江大学城站下

  • 地址:上海市浦东新区惠南镇拱极路2151号

    乘车路线:地铁16号线惠南站

总部地址:北京市海淀区中关村大街28-1号6层601 总部电话:400-779-6688 总部:北京新航道教育文化发展有限责任公司

Copyright © www.xhd.cn All Rights Reserved 京ICP备05069206

  • 微信公众号
  • 微信社群