Streams and rivers carry soil and rocks from one location to another. But there is another way for these geological materials
to move. Scientists call this process “aeolian transport.” In aeolian transport, winds move small particles of soil or rock over
potentially great distances. Geologist Melisa Diaz and her team studied dust in Antarctica to ﬁnd out if it was moved by
aeolian transport. They discovered that the dust matched geological material in Australia. Aeolian transport had carried it
from one continent to another, across thousands of miles of open ocean.
It presents Melisa Diaz’s remarks about diﬃculties that her team encountered.
It introduces a scientiﬁc term that is used in the discussion that follows.
It emphasizes the surprising nature of the ﬁndings that are presented.
It explains the difference between two kinds of geological material.
Choice B is the best answer because it most accurately describes the function of the underlined portion in the text as a
whole. The ﬁrst two sentences introduce the idea that soil and rocks can be moved from one location to another by
something other than rivers and streams. The underlined sentence then states that the term used by scientists to refer to
this process is “aeolian transport.” The discussion that follows explains what aeolian transport is (the movement of small
geological materials over potentially great distances by the wind) and describes an example of a study that found that dust
particles had been moved by aeolian transport from Australia to Antarctica. Thus, the underlined portion introduces a
scientiﬁc term that is used in the discussion that follows.
Choice A is incorrect because the underlined portion of the text doesn’t present any remarks from Melisa Diaz, nor does it
suggest that Diaz and her team encountered diﬃculties in their study. Instead, the phrase in quotation marks in the
underlined portion simply presents a term that is used by scientists to refer to a speciﬁc process discussed in the
text. Choice C is incorrect because nothing in either the underlined portion or the text as a whole suggests that the ﬁndings
of the study presented in the text were surprising or unexpected. In fact, the text suggests that Diaz and her team wanted to
see if aeolian transport could explain the appearance of certain geological materials in Antarctica, and their ﬁndings did
indeed conﬁrm the involvement of aeolian transport. Choice D is incorrect. Although the ﬁrst sentence of the text mentions
soil and rocks, which are two different kinds of geological material, the underlined portion doesn’t refer to these materials,
nor does it explain the difference between them. Rather, the underlined portion introduces the scientiﬁc term “aeolian
transport,” which is used in the discussion that follows.