Question

ZEBRASLesley Evans Ogden1Why zebras have stripes has long perplexed naturalists and continues to challenge scientists. Among the proposed explanations are that stripes promote social cohesion, regulate temperature, or confuse predators and biting flies. The matter, however, is far from settled.2Ecologist Brenda Larison of the University of California, Los Angeles, and six colleagues decided to have a fresh look at three hypotheses: predator evasion, thermoregulation, and biting fly avoidance. Plains zebras, Equus quagga, show a marked geographic variation in their stripes, which range from heavy black-and-white patterns covering the entire body to thinner, lighter stripes restricted to particular areas. For example, a now extinct subspecies from South Africa, E. q. quagga, had stripes on its neck, head, and torso but not on its belly or legs. The difference from region to region prompted the team to search for associations between environmental factors and striping patterns.3The researchers chose sixteen populations of plains zebras and photographed a minimum of eight animals per site. Using image-processing software, they noted the number of stripes and their length, thickness, and color saturation on the legs, torso, and belly. They also gathered data on twenty-nine environmental variables, including temperature, precipitation, soil moisture, leaf water content, and tree canopy cover. In addition, they used the Food and Agricultural Organization's published distribution of tsetse flies and modeled the historic geographic distribution of lions and tsetse flies. The team then ran a computer model and looked at which variables best predicted the observed geographic variation of stripes.4Surprisingly, they found no clear link between striping patterns and escape from predators or avoidance of biting flies. Instead, temperature was the strongest predictor of stripe variation. Plains zebras living in warmer regions had thicker, more defined stripes than those in cooler regions. This, say the authors, seems to support the idea that contrasting black and white stripes lead to differential air currents, potentially giving the zebras an onboard air conditioner. Such a mechanism has previously been proposed but still remains to be investigated directly. Another untested possibility is that it’s not tsetse fly distribution that matters, but rather the distribution of the disease-causing parasites carried by the flies. 1It's something I want to followup on,"says Larison, who is also studying the genetics that underlies zebra striping.5"We usually think about zebra stripes in terms of benefits of striping, but the fact that they lose their striping in certain areas suggests that perhaps there are also some costs," she says. The mystery of zebra stripes is still being resolved, but for now, one possible explanation has been seriously considered.Adapted from Natural History, March 2015.31In paragraph 1, the sentence *The matter, however, is far from settled" most likely means the same as which of the following?A Scientists and naturalists believe they are close to a solid understanding of the origin and function of zebra stripes.B Scientists and naturalists have not yet arrived at a solid understanding of the purpose of zebra stripes.C Scientists and naturalists are still unable to explain why different striping patterns are often found among members of the same zebra species.D The unsettled, migratory nature of zebra herds has impeded practical scientific research.E Scientists and naturalists believe that only three hypotheses could reasonably explain the purpose of zebra stripes

Answer 1

Olá, Josiphenayara5149.

Do primeiro parágrafo, podemos interpretar que:

- a ocorrência dos padrões de listras nas zebras é um tópico que ainda desperta interesse nos cientistas e nos pesquisadores

- há hipóteses para explicar o porquê elas existem, como ferramenta de coesão social, ou por função metabólica ou para proteção contra predadores

- apesar das hipóteses, a questão (o porquê de as zebras possuirem listras) ainda está longe de ter sido resolvida.

As duas alternativas que mostram que o assunto ainda gera dúvidas são as alternativas b e c. Entretanto, no parágrafo não há menção sobre diferenças nas listras de zebras da mesma espécie. Portanto, a sentença que melhor expressa a mesma ideia que "the matter, however, is far from settled" é "scientists and naturalists have not yet arrived at a solid understanding of the purpose of zebra stripes".

Resposta correta: alternativa B.

Espero ter ajudado.