Question 164·Hard·Rhetorical Synthesis
While conducting research, a student compiled the following notes:
- Coral reefs provide habitat for roughly 25% of all known marine species.
- Corals rely on symbiotic algae, called zooxanthellae, for most of their energy.
- Elevated sea temperatures cause corals to expel zooxanthellae, a process known as bleaching.
- Large-scale bleaching events have increased in frequency over the past three decades.
The student wants to craft a sentence that emphasizes the growing threat climate change poses to coral reef ecosystems and supports this claim with specific evidence. Which choice most effectively accomplishes these goals?
For rhetorical synthesis questions based on notes, first restate the goal in your own words (for example: "I need a sentence that shows a growing climate threat and backs it up with facts"). Then scan the notes to find which ones relate directly to that goal (cause, trend over time, importance, consequences). When you check the answer choices, eliminate any that (1) leave out a key part of the goal (like the threat, the cause, or the evidence), or (2) merely repeat one note without combining ideas. Prefer the option that most efficiently links cause and effect, shows change or seriousness (words like "increasingly," "at serious risk"), and uses a concrete detail (such as a statistic) to support the main claim.
Hints
Focus on the goal in the question
Underline the words "growing threat," "climate change," and "supports this claim with specific evidence" in the prompt. Which options actually talk about a serious danger and not just describe how reefs or corals work?
Use the notes strategically
Look back at the notes: one mentions elevated sea temperatures, another mentions that bleaching events are happening more often, and another gives a percentage about species in reefs. Which option weaves together these kinds of details instead of just repeating one fact?
Check for cause, trend, and impact
Ask yourself: Which choice shows cause (warming seas), a trend (more frequent events), and impact (how important or threatened the reefs are)? Eliminate any option that leaves out one of these three ideas.
Step-by-step Explanation
Restate the task
The question asks for a single sentence that (1) emphasizes the growing threat climate change poses to coral reef ecosystems and (2) supports this claim with specific evidence from the notes. Any correct answer must do both parts.
Identify the most relevant notes
From the four notes, focus on the ones that relate to a growing threat and to evidence:
- Growing threat from climate change:
- Elevated sea temperatures cause bleaching.
- Large-scale bleaching events have increased in frequency over the past three decades.
- Evidence showing why this threat matters:
- Coral reefs provide habitat for roughly 25% of all known marine species.
A strong sentence will connect warming temperatures to more bleaching and to the importance of reefs for many species.
Translate the task into required sentence features
Before looking closely at the options, decide what the correct sentence must include:
- A clear idea that climate-change-related warming is causing a growing problem (trend words like "increased" or "increasingly frequent" are helpful).
- A statement that this situation puts coral reefs or reef ecosystems in serious danger or risk.
- Specific evidence, such as a statistic (like "about a quarter" or "25%" of marine species) or mention of the increase in bleaching events.
Any option missing the idea of serious risk, the climate-change connection, or the concrete evidence should be eliminated.
Match the best option to these requirements
Only choice D combines all the needed elements in one sentence: it links elevated sea temperatures (from climate change) to increasingly frequent bleaching events (showing the growing threat) and then states that coral reefs are now at serious risk, while also giving specific evidence that they shelter about a quarter of all marine species. This both emphasizes the danger and supports it with concrete facts, so the correct answer is: "Because elevated sea temperatures trigger increasingly frequent bleaching events, coral reefs that shelter about a quarter of all marine species are now at serious risk."