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Chapter 118

2021 : B

READING2 · 44 questions

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Chapter 118 · 2021 : B · READING2

Prehistoric PrintingPaleontologists are using modern technology to gaina greater understanding of the distant past. With the aidof computed tomography (CT) scanning and 3-Dprinting, researchers are able to create accurate models ofprehistoric fossils. (1) These models have expanded researchers’ knowledge of ancient species and (2) swearto advance the field of paleontology in the years to come.CT scanners use X-rays to map the surface of a fossilin minute detail, recording as many as one million datapoints to create a digital blueprint. A 3-D printer thenbuilds a polymer model based on this blueprint, much asa regular computer printer reproduces digital documentson paper. (3) Whereas the head of an ordinary computerprinter moves back and forth while printing ink ontopaper, the corresponding part of a 3-D printer moves inmultiple dimensions while squirting out thin layers ofmelted polymer plastic. The plastic hardens quickly,(4 )it allows the printer to build the layers of the finalmodel. Compared with older ways of modeling fossils,scanning and printing in this way is extremely versatile. [1] One significant benefit of 3-D printingtechnology is its ability to create scale reproductions offossils. [2] But now 3-D scale models can be rearrangedwith ease, which is a huge boon to scientists. [3] A teamled by Drexel University professor Kenneth Lacovara ismaking models of dinosaur bones one-tenth the bones’original sizes (5) in order to learn how they fit togetherwhen the animals were alive. [4] In the past, suchresearch was limited by the weight and bulk of the fossilsas well as(6)its preciousness and fragility. [5] In manycases, scientists had to rearrange bones virtually, usingartists’ renderings. (7)Because CT scanners can map objects that areimpossible to excavate, CT scanning and 3-D printingcan also be used to reproduce fossils that scientistscannot observe firsthand. (8) By contrast, researchers from the National Museum of Brazil (9) has relied onthis technique to study a fossilized skeleton that wasdiscovered protruding from a rock at an old São Paulorailroad site. (10) The fossil was too delicate to beremoved from the rock. Because of the fossil’s delicatenature, the team dug up a block of stone around the fossiland brought it to their lab. With the aid of a CT scannerand a 3-D printer, they were able to produce a resinmodel of the fossil. Examining the model, the researchersdetermined that (11) one had found a new species, a75-million-year-old crocodile. While not every discoverywill be as dramatic as this one, paleontologists anticipatefurther expanding their knowledge of ancient life-formsas CT scanning and 3-D printing continue to make fossilsmore accessible.

At this point, the writer is considering adding the
following sentence.
Fossils provide paleontologists with a convenient
way of estimating the age of the rock in which
the fossils are found.
Should the writer make this addition here?
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