問題詳情

Passage #47-50      DNA transfers naturally between organisms. Several natural mechanisms allow gene flow across species. These occurin nature on a large scale – for example, it is one mechanism for the development of antibiotic resistance in bacteria.Movement occurs over an evolutionary time scale.    The introduction of foreign germplasm into crops has been achieved by traditional crop breeders by overcomingspecies barriers. A hybrid cereal grain was created in 1875, by crossing wheat and rye. Since then important traitsincluding dwarfing genes and rust resistance have been introduced. Plant tissue culture and deliberate mutations haveenabled humans to alter the makeup of plant genomes. The first genetically modified crop plant was produced in 1982,an antibiotic-resistant tobacco plant. The first field trials occurred in France and the USA in 1986, when tobacco plantswere engineered for herbicide resistance.    GM foods are controversial and the subject of protests, vandalism, referenda, legislation, court action and scientificdisputes. The controversies involve consumers, biotechnology companies, governmental regulators, non-governmentalorganizations and scientists. There is a scientific consensus that currently available food derived from GM crops poses nogreater risk to human health than conventional food, but that each GM food needs to be tested on a case-by-case basisbefore introduction.    No reports of ill effects have been documented in the human population from GM food. Although GMO labeling isrequired in many countries, the United States Food and Drug Administration does not require labeling, nor does itrecognize a distinction between approved GMO and non-GMO foods.     Advocacy groups such as Center for Food Safety, Union of Concerned Scientists, Greenpeace and the World WildlifeFund claim that risks related to GM food have not been adequately examined and managed, that GMOs are notsufficiently tested, and that regulatory authorities and scientific bodies are too closely tied to industry. Some studies haveclaimed that genetically modified crops can cause harm; a 2016 review that reanalyzed the data from six of these studiesfound that their statistical methodologies were flawed and did not demonstrate harm, and said that conclusions aboutGMO crop safety should be drawn from "the totality of the evidence... instead of far-fetched evidence from single studies"
47. What does the passage mainly discuss?
(A) The history of genetically modified foods.
(B) The reason why genetically modified food was invented.
(C) The advantages and disadvantages of genetically modified foods.
(D) How genetically modified foods came to exist and the controversies about it.

參考答案

答案：D
難度：困難0.347826
統計：A(3),B(6),C(5),D(8),E(0)

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