百思不得其解的一道题

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.

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！

真是搞不懂啊

文章不是已经说了，odorant是perceived consciously的吗？

而且后面的例子不也正是用来证明这个事实的么？

那么这篇文章的purpose为什么会是E？

检查了答案，这题却不是争议题

期待NN解答