Question 45·Hard·Text Structure and Purpose
Oceanographer Sylvia Earle once compared the planet’s ocean to a living library, each species representing a volume in an immeasurably vast collection. Yet, as political leaders weigh the costs of marine conservation against immediate economic gains, they often overlook the long-term benefits of protecting this “library.” A 2022 study by the Global Seascape Initiative calculated that fully protected marine reserves could yield six dollars in ecological services for every dollar spent on enforcement. Policymakers might remain skeptical, but the study’s model predicts that these reserves would restore nearly half of currently depleted commercial fish stocks within just ten years.
Which choice best describes the function of the underlined portion in the text as a whole?
For SAT questions asking about the function of a sentence or phrase, first summarize the main point of the whole passage or paragraph in your own words. Then paraphrase the target sentence and ask, “What job is this sentence doing here—giving an example, offering evidence, making a concession, defining a term, or something else?” Finally, eliminate choices that introduce ideas not mentioned in the passage (like prior studies or methods not discussed) or that describe a tone (critical, doubtful, etc.) that doesn’t match the wording. Focus on what the sentence actually adds to the argument, not just on its content in isolation.
Hints
Zoom out to the paragraph’s purpose
Before thinking about the underlined sentence, ask: What is the author trying to convince the reader of in this whole paragraph?
Look closely at what the underlined sentence adds
Read the sentence right before the underlined part and then the underlined part itself. What new kind of information does the underlined sentence add to what the study has already been said to show?
Decide if the tone is supportive or critical
Is the underlined sentence raising doubts about the study, or is it giving more reason to believe that marine reserves are valuable? Think about whether the wording sounds positive, negative, or neutral.
Check for details mentioned (or not mentioned) in the passage
Some answer choices mention things like comparisons to previous estimates or doubts about methodology. Ask yourself: does the passage actually talk about these things anywhere?
Step-by-step Explanation
Identify the main point of the passage
First, summarize what the whole paragraph is trying to argue.
- The author starts with a metaphor about the ocean as a “living library,” suggesting it is valuable.
- Then the author criticizes political leaders for focusing on immediate economic gains and ignoring long-term benefits of protecting the ocean.
- A 2022 study is introduced that says fully protected marine reserves could yield six dollars in ecological services for every dollar spent.
So the passage as a whole is arguing that marine reserves and conservation are valuable and beneficial in the long term, even if they seem costly in the short term.
Understand what the underlined sentence says
Now focus on the underlined portion:
“the study’s model predicts that these reserves would restore nearly half of currently depleted commercial fish stocks within just ten years.”
What information does this add?
- It is a prediction made by the study’s model.
- It is specific and quantitative: nearly half of depleted commercial fish stocks.
- It includes a time frame: within ten years.
So this sentence provides a concrete projection about how much and how quickly fish stocks could recover.
Connect the underlined sentence to the passage’s argument
Ask: How does this specific prediction help the author’s overall point?
- Earlier, the passage mentions a 6-to-1 return in ecological services, which suggests economic value.
- The underlined prediction shows that fish stocks—a key commercial resource—would recover significantly in a relatively short time.
- That recovery would support future fishing and related industries, which ties directly into long-term economic and ecological benefits.
So the sentence is functioning as supporting evidence for the claim that marine reserves are beneficial over time, not as a criticism or a doubt about the study.
Match the function to the best choice
Now compare this understanding with the answer options:
- The sentence is a specific, numeric projection (a prediction) that shows strong recovery of valuable commercial fish stocks within ten years.
- This directly backs up the passage’s claim that fully protected marine reserves pay off in the long run, both ecologically and economically.
Therefore, the correct choice is: It offers a concrete projection to support the argument that marine reserves are economically beneficial in the long term.