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 (10) 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 waysin which the vomeronasal organand the main olfactory systernprocess chemicals.（没题到）
B.summarize the debate over therole the vomeronasal organ plays （没提到）in odor perception
C.present some of the issuesinvolved in the debate overwhat constitutes a pheromone（没提到）
D.propose a new definition ofpheromones based on recentresearch
E.argue that pheromones should beclassified as a type of odorant（也没有这样说呀，文中的举例了两种系统对应处理两种化学物质，及一些特例）
这题我选了d ，文中是说了一种new definition 只是没有summerize吧。谁能帮帮忙啊
Q9: The primary purpose of the passage is to
A.compare and contrast the waysin which the vomeronasal organand the main olfactory systernprocess chemicals.（没题到）
B.summarize the debate over therole the vomeronasal organ plays （没提到）in odor perception
C.present some of the issuesinvolved in the debate overwhat constitutes a pheromone（没提到）
D.propose a new definition ofpheromones based on recentresearch
E.argue that pheromones should beclassified as a type of odorant（也没有这样说呀，文中的举例了两种系统对应处理两种化学物质，及一些特例）
这题我选了d ，文中是说了一种new definition 只是没有summerize吧。谁能帮帮忙啊 | 
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发表于 2010-5-2 13:15:38
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