GWD26-9

Q7 to Q9

There is no consensus among

researchers regarding what qualifies a

substance as a pheromone. While most

Line agree on a basic
definition of pheromones

(5) 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

(15) 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

(20) 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

(25) 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 phero-

(30) mones 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

(35) the VNO, and they use
this signal to track

their
prey.

Q9

The primary purpose of the
pas-

sage 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

constitute? 说了pheromones的成分么？

弱弱地说 我觉得 主要还说p与o的区别

support c

constitute有”被认为是“的意思

C

我也是C

involved in the debate over

what constitutes a pheromone

要看后半部分   根本都无关