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- Fri Jun 23, 2017 1:31 pm
#36249
Complete Question Explanation
(See the complete passage discussion here: lsat/viewtopic.php?t=14432)
The correct answer choice is (E)
Although this question specifically refers to lines 29-30, it is advantageous to have an understanding
of the role each paragraph plays in the overall context of the passage. Since the second paragraph
describes the use of lichenometry in dating past earthquakes, the author’s primary purpose in
referring to the growth rate of North American lichen species is to help us understand how fast
lichens grow. This is important, since lichen growth rate can help us associate the diameter of lichens
with the timing of past earthquakes.
Answer choice (A): The author never intended to emphasize the rapidity with which lichen colonies
establish themselves on newly exposed rock surfaces. The fact that they do so rather quickly is
mentioned in line 25, but the rate of 9.5 millimeters per century measures lichen growth rate after
they have colonized the rock surface.
Answer choice (B): There is no reason to suspect that the North American lichen species has a
particularly slow rate of growth. We have no information to determine its growth rate relative to
other lichen species.
Answer choice (C): Environmental conditions can indeed alter lichens’ rate of growth; however, that
discussion takes place at the very end of the passage, not in the second paragraph.
Answer choice (D): Although lichenometry does work best for dating earthquakes that occurred
in the last 500 years, the rate of growth of North American lichen species does not support that
statement. According to the second paragraph, lichens grow at a slow but constant rate for as long
as 1,000 years, if left undisturbed. The reason why lichenometry works best for dating more recent
earthquakes is because a shorter timeframe can minimize the influence of factors that affect lichen
growth rates. That discussion takes place much later in the passage, not in the middle of the second
paragraph.
Answer choice (E): This is the correct answer. By understanding the timescale on which lichen
growth occurs, we can get a better sense of why lichen size is a useful indicator of the frequency and
location of past earthquakes.
(See the complete passage discussion here: lsat/viewtopic.php?t=14432)
The correct answer choice is (E)
Although this question specifically refers to lines 29-30, it is advantageous to have an understanding
of the role each paragraph plays in the overall context of the passage. Since the second paragraph
describes the use of lichenometry in dating past earthquakes, the author’s primary purpose in
referring to the growth rate of North American lichen species is to help us understand how fast
lichens grow. This is important, since lichen growth rate can help us associate the diameter of lichens
with the timing of past earthquakes.
Answer choice (A): The author never intended to emphasize the rapidity with which lichen colonies
establish themselves on newly exposed rock surfaces. The fact that they do so rather quickly is
mentioned in line 25, but the rate of 9.5 millimeters per century measures lichen growth rate after
they have colonized the rock surface.
Answer choice (B): There is no reason to suspect that the North American lichen species has a
particularly slow rate of growth. We have no information to determine its growth rate relative to
other lichen species.
Answer choice (C): Environmental conditions can indeed alter lichens’ rate of growth; however, that
discussion takes place at the very end of the passage, not in the second paragraph.
Answer choice (D): Although lichenometry does work best for dating earthquakes that occurred
in the last 500 years, the rate of growth of North American lichen species does not support that
statement. According to the second paragraph, lichens grow at a slow but constant rate for as long
as 1,000 years, if left undisturbed. The reason why lichenometry works best for dating more recent
earthquakes is because a shorter timeframe can minimize the influence of factors that affect lichen
growth rates. That discussion takes place much later in the passage, not in the middle of the second
paragraph.
Answer choice (E): This is the correct answer. By understanding the timescale on which lichen
growth occurs, we can get a better sense of why lichen size is a useful indicator of the frequency and
location of past earthquakes.