▶ Your Answer :
Both the lecturer and the writer are
discussing about the situation of decline of yellow cedar populations. The
writer suggests three hypotheses to explain this phenomenon. On the other hand,
the lecturer asserts the writer's arguments are not plausible.
To begin with, the lecturer claims that
insect parasites including the cedar bark beetle cannot be the factor of the
major reason of declining the yellow cedar trees. This is because the species
are strong enough to resist the beetle. To be specific, they have powerful
toxic chemical substances to overcome infestation. Therefore, it is unlikely to
suffer due to the beetle. This counters the reading passage's idea that the
cedar bark beetle would be the reason of dying the yellow cedar.
Next, the lecturer insists that brown bears
are not responsible for declining the yellow cedars, comparing the bears' living
area with the trees' habitat. The yellow cedars still have been dying in some
regions where the bears are not living. This contradicts the reading passage's
claim that brown bears' aggressive feeding habit like clawing to consume sugar
and berries would lead the yellow cedar to the crisis of its population
numbers.
Finally, the lecturer argues that the
climate alteration did not significantly affect the problem of the yellow
cedars. According to the lecturer, the trees have been dying in the low elevation,
where it is warm. However, the elevation has to be higher, in other words the
place has to be cold, for making influences on the trees by freezing their
roots. This goes against the reading passage's assertion that gradual change of
climate freezes the tree’s roots, and leads them to be dead.
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