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THE CAMBRIAN EXPLOSION

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  6. Which of the following best describes the relationshipbetween Paragraph2 and Paragraph3?

  Paragraph2 puts forward severalscientific claims, one of which is rejected in Paragraph3

  Paragraph2 posesseveral questions, and Paragraph3offers a possible answer to one ofthem

  Paragraph2 presents outdated traditional views, whileParagraph3presents the current scientific conclusions.

  Paragraph2 introducesa generalization that is illustrated by specific examples inParagraph3

  Paragraph3: One interpretation regarding the absence offossils during this important 100-million-year period is that early animals weresoft bodied and simply did not fossilize. Fossilization of soft-bodied animalsis less likely than fossilization of hard-bodied animals, but it does occur.Conditions that promote fossilization of soft-bodied animals include very rapidcovering by sediments that create an environment that discourages decomposition.In fact, fossil beds containing soft-bodied animals have been known for manyyears.

  7. The word promote in the passage is closest in meaningto

  complicate

  prevent

  encourage

  affect

  Paragraph4:The Ediacara fossil formation, which contains the oldest known animal fossils,consists exclusively of soft-bodied forms. Although named after a site inAustralia, the Ediacara formation is worldwide in distribution and dates toPrecambrian times. This 700-million-year-old formation gives few clues to theorigins of modern animals, however, because paleontologists believe itrepresents an evolutionary experiment that failed. It contains no ancestors ofmodern animal groups.

  8. Which of the following is NOT mentioned inParagraph4 as being true of the Ediacara formation?

  It contains fossils thatdate back to the Precambrian period.

  It contains only soft-bodied animalfossils.

  It is located on a single site in Australia.

  It does notcontain any fossils of the ancestors of modern animals.

 

  Paragraph5: Aslightly younger fossil formation containing animal remains is the Tommotianformation, named after a locale in Russia. It dates to the very early Cambrianperiod, and it also contains only soft-bodied forms. At one time, the animalspresent in these fossil beds were assigned to various modern animal groups, butmost paleontologists now agree that all Tommotian fossils represent unique bodyforms that arose in the early Cambrian period and disappeared before the end ofthe period, leaving no descendants in modern animal groups.

  9. Which ofthe sentences below best expresses the essential information in the highlightedsentence in the passage? Incorrect choices change the meaning in important waysor leave out essential information.

  The animals found in the Tommotianfossil bed were once thought to belong to a variety of modern animal groups, butnow they are thought to have descended from a single group.

  Animals in theTommotian fossil beds were initially assigned to modern animal groups but arenow thought to belong to groups that emerged and died out during the Cambrianperiod.

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