algae. However, recent research has shown that such bleaching occurs even in
the absence of light.
Tolleter and his team of scientists showed that bleaching still occurs
even if the algae are heat-stressed in the dark. This finding is significant
because during the dark, the algae’s photosynthetic machinery is turned
off, meaning that the heat’s effect on the algae must occur by disrupting
cellular processes other than photosynthesis. Tolleter’s findings, though
keeping intact the belief that ocean temperatures affect bleaching, question
the exact mechanism through which this bleaching occurs. Future research
is necessary to identify the other routes by which bleaching occurs, but
these findings, by implicating additional mechanisms in the process of
bleaching, should point scientists toward new directions in identifying ways
to decelerate this bleaching process.
As you probably recognized, there are a lot of details in this passage, along with
terminology that may not be completely familiar to you. But let’s try to take a big-
picture approach toward the passage. In the beginning of the passage, the author
introduces an important term: “bleaching.” An efficient reader would slow down
to understand this term. Once you understand what bleaching is, your next step is
to identify the author’s main purpose. He gives you “the prevailing theory” for why
bleaching occurs, but is the author’s main purpose to describe this theory? No. In
the last sentence of the first paragraph, the contextual clue “However” indicates
that the author’s purpose is to show that bleaching can happen for reasons other
than disrupting photosynthesis. Now that you know why the author has written
the passage, your next step is to identify the role of the evidence—in this case, why
the author wrote the second paragraph.
The last sentence of the first paragraph questions the prevailing theory, and
the second paragraph is spent providing evidence for why this theory has been
questioned. Though the terminology and processes might be difficult to follow,
you know that the role of this paragraph is to explain why the prevailing theory of
the disruption of photosynthesis is not adequate to account for the phenomenon of
bleaching. Now that you have a big-picture understanding of the passage, you can
move on to the questions.Question Types
This section reviews common GRE question-types by seeing how they relate to
the previous passage. But before that, keep in mind two important guidelines you
should follow when answering any Reading Comprehension question:■ Eliminate any choices that contradict the passage.
■ Eliminate any choices that are irrelevant to the question being asked.1520CHAPTER 6 ■ READING COMPREHENSION 12902-GRE-Test-2018_107-172.indd 129 13/05/17 11:06 am