Even more than mountainside slides of mud or snow, naturally

Even more than mountainside slides
of mud or snow, naturally occurring forest
fires promote the survival of aspen trees.
Line Aspens’ need for fire may seem illogical
(5) since aspens are particularly vulnerable
to fires; whereas the bark of most trees
consists of dead cells, the aspen’s bark
is a living, functioning tissue that—along
with the rest of the tree—succumbs quickly
(10) to fire.
The explanation is that each aspen,
while appearing to exist separately as
a single tree, is in fact only the stem or
shoot of a far larger organism. A group
(15) of thousands of aspens can actually
constitute a single organism, called a
clone, that shares an interconnected root
system and a unique set of genes. Thus,
when one aspen—a single stem—dies,
(20) the entire clone is affected. While alive,
a stem sends hormones into the root
system to suppress formation of further
stems. But when the stem dies, its
hormone signal also ceases. If a clone
(25) loses many stems simultaneously, the
resulting hormonal imbalance triggers a
huge increase in new, rapidly growing
shoots that can outnumber the ones
destroyed. An aspen grove needs to
33
(30) experience fire or some other disturbance
regularly, or it will fail to regenerate and
spread. Instead, coniferous trees will
invade the aspen grove’s borders and
increasingly block out sunlight needed by
the aspens.



Q36:
It can be inferred from the passage that when aspen groves experience a “disturbance”
(line 30), such a disturbance
A. leads to a hormonal imbalance within an aspen clone
B. provides soil conditions that are favorable for new shoots
C. thins out aspen groves that have become overly dense
D. suppresses the formation of too many new aspen stems
E. protects aspen groves by primarily destroying coniferous trees rather than aspens
Answer:
--------------------------------------------------------------------------------
Q37:
The author of the passage refers to “the bark of most trees” (line 6) most likely in order to
emphasize the
A. vulnerability of aspens to damage from fire when compared to other trees
B. rapidity with which trees other than aspens succumb to destruction by fire
C. relatively great degree of difficulty with which aspens catch on fire when
compared to other trees
D. difference in appearance between the bark of aspens and that of other trees
E. benefits of fire to the survival of various types of trees
Answer