Fill in the blank. The formation of cork layers in
response to damage or infection is an example of blank defense in plants. (A) A biochemical, (B) a
preexisting structural, or (C) an induced structural.
To answer this question, let’s
first review why the formation of cork layers happens.
When plant tissues like, for
example, the bark on a tree are damaged, an entrance point for a pathogen to infect
the plant is created in the outer protective layer of the plant. In order to block the opening
created by the damage and prevent outside pathogens or other disease-causing
elements from entering the inner tissues of the plant, some plants can form layers
of cork. What kind of a defense is that?
We can easily see that this defense
involves physically blocking the entrance of pathogens and does not use a chemical
substance. It is therefore a structural, not a
biochemical, defense. Also, since this formation happens
as a response to damage, it isn’t a preexisting defense, like, for example, the
layer of bark on a tree trunk would be. It is instead an induced defense or
a defensive structure that is only produced in response to an actual attack or
Therefore, the correct answer must
be (C). The formation of cork layers in
response to damage or infection is an example of an induced structural defense in