Question 92·Medium·Central Ideas and Details
Marine biologists studying reefs in the eastern Caribbean recently identified a population of staghorn coral that appears unusually tolerant of rising ocean temperatures. In controlled lab experiments, the coral maintained normal growth rates even when water temperatures mimicked those expected later this century. Lead researcher Dr. Maya Chen hopes that genetic analysis of the hardy coral will help conservationists select strains for reef restoration projects worldwide.
Which choice best states the main topic of the text?
For main-topic questions, first quickly summarize the passage in your own words in one short sentence, then compare that summary to each answer choice. Eliminate choices that focus on a detail (like a method, a single result, or a person’s name) or that introduce ideas not supported by the text (like broad policies or life stories). The correct answer will match the overall focus of the whole paragraph, especially what’s set up in the first sentence and reinforced or concluded in the last sentence.
Hints
Use the whole paragraph, not one detail
Reread the paragraph and ask: If I had to explain this in one sentence to a friend, what would I say? Focus on that big picture idea.
Check the beginning and end
Look especially at the first sentence (how the situation is introduced) and the last sentence (what the researcher hopes to do). What do they have in common?
Compare what each option mainly talks about
Ask yourself for each choice: Is the paragraph mostly about this topic, or is this off-topic or only briefly mentioned?
Step-by-step Explanation
Identify the task
The question asks for the main topic of the text. That means you need to decide what the entire paragraph is mostly about, not a small detail or side point.
Summarize the paragraph in your own words
Restate the paragraph briefly:
- Marine biologists studying reefs in the eastern Caribbean found a population of staghorn coral.
- This coral appears unusually tolerant of rising ocean temperatures and kept normal growth rates in warm-water experiments.
- Dr. Maya Chen hopes that analyzing this coral’s genes will help conservationists choose strains for reef restoration.
This summary centers on a special coral population that can handle warmer water and how that could help future conservation.
Match the general focus to the choices
Look at what each answer choice emphasizes:
- One choice talks about a method for measuring growth.
- One talks about efforts to reduce climate change in a region.
- One talks about a person’s career achievements.
- One talks about a discovery related to a special type of coral.
Ask: Which of these matches the summary you made of the paragraph’s main focus?
Select the answer that best fits the main idea
The text is about scientists discovering a population of staghorn coral that withstands higher temperatures and the potential use of that discovery for reef restoration. The only choice that captures this central idea is C) Discovery of heat-resistant staghorn coral.