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找不到GWD 26的RC讨论。哪位NN知道？ GWD 26-Q7 to Q9 There is no consensus among researchers regarding what qualifies a substance as a pheromone. While most agree on a basic definition of pheromones as chemicals released by one individual of a species which, when detected by another individual of the same species, elicit a specific behavioral or physiological response, some researchers also specify that the response to pheromones must be unconscious. In addition, the distinction between pheromones and odorants— chemicals that are consciously detected as odors---can be blurry and some researchers classify pheromones as a type of odorant. Evidence that pheromone responses may not involve conscious odor perception comes from the finding that in many species, pheromones are processed by the vomeronasal (or accessory olfactory) system, which uses a special structure in the nose, the vomeronasal organ (VNO), to receive chemical signals. The neural connections between the VNO and the brain are separate from those of the main olfactory system, whose processing of odorants triggers sensations of smell. But while the VNO does process many animal pheromone signals, not all animal pheromones work through the VNO. Conversely, not all chemical signals transmitted via the VNO quality as pheromones. For example, garter snakes detect a chemical signal from earthworms—one of their favorite foods—via the VNO, and they use this signal to track their prey.
Q9: The primary purpose of the passage is to A. compare and contrast the ways
in which the vomeronasal organ
and the main olfactory systern
process chemicals. B. summarize the debate over the
role the vomeronasal organ plays in odor perception C. present some of the issues
involved in the debate over
what constitutes a pheromone D. propose a new definition of
pheromones based on recent
research E. argue that pheromones should be
classified as a type of odorant 答案是E，我选B。不明白为什么是E。哪位NN指点指点？ | 
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发表于 2008-7-19 15:10:00
