Question 17·Medium·Central Ideas and Details
Marine biologist Rachel Warren and her team deployed networks of underwater microphones across the Atlantic and Pacific Oceans to record humpback whale vocalizations for three consecutive years. The researchers identified a new sequence of notes that first appeared near the Cook Islands and then steadily surfaced in recordings made thousands of miles to the east, where it replaced the whales’ previous songs. The study concludes that humpback whales are able to share and adopt novel songs over vast distances in a relatively short period of time.
Which choice best states the main idea of the text?
For main idea questions on the SAT, first read the entire short passage, then quickly restate its point in your own words in 5–10 seconds, focusing especially on any sentence that states what a study “concludes” or what a passage “shows.” Next, scan the answer choices and eliminate any that (1) introduce ideas not mentioned in the text, (2) focus on minor details like tools or locations, or (3) exaggerate or distort what the passage actually says. Finally, pick the choice that most closely matches your brief summary without adding or changing information.
Hints
Focus on the study’s purpose and result
Ask yourself: What were the scientists trying to learn by recording whale vocalizations for three years in different oceans, and what did they find out?
Pay attention to the last sentence
Look closely at the sentence that begins, “The study concludes that…” Questions about the main idea are often answered by the author’s stated conclusion or takeaway.
Watch out for new or extra information
Check each answer choice and ask: Does the passage actually mention this idea, or is it adding something about species, volume, or equipment that was never discussed?
Connect the evidence to the conclusion
Think about how the new sequence of notes that starts near the Cook Islands and later appears thousands of miles away helps the researchers reach their conclusion. Then choose the option that best reflects that overall finding.
Step-by-step Explanation
Identify what the question is asking
The question asks, “Which choice best states the main idea of the text?” That means you are looking for the overall conclusion or main point of the entire passage, not a small detail or something that is not mentioned.
Summarize the key points of the passage
Go sentence by sentence:
- First sentence: Describes how Warren and her team used underwater microphones in both the Atlantic and Pacific to record humpback whale sounds for three years.
- Second sentence: Says they found a new sequence of notes that first showed up near the Cook Islands, then later appeared thousands of miles to the east and replaced the whales’ older songs there.
- Third sentence: Gives the study’s conclusion about what these observations show.
Overall, the passage is about what this pattern of song change tells us about humpback whales, not about the equipment itself or differences between oceans.
Locate the explicit statement of the main conclusion
The last sentence starts, “The study concludes that…” That is the author directly stating the main idea or takeaway of the entire experiment. Whatever the main idea is, it must match that conclusion and fit with the earlier description of songs appearing in one place and then showing up far away, replacing older songs.
Eliminate choices that introduce unrelated or unsupported ideas
Check each option against the passage:
- Choice A talks about whales in the Pacific singing louder than those in the Atlantic. The passage never mentions volume or compares loudness.
- Choice C says biologists discovered a new species near the Cook Islands using microphones. The text only mentions a new sequence of notes, not a new species.
- Choice D claims underwater microphones must be replaced every year because of corrosion. The passage does not mention any maintenance or damage to the equipment.
All three of these bring in new information that is not supported by the text, so they cannot be the main idea.
Match the remaining choice to the stated conclusion
The only remaining option is Choice B: “Research indicates that humpback whales quickly transmit new songs across vast ocean regions.” This directly matches the study’s conclusion that whales can share and adopt new songs over great distances in a short time, and it fits the evidence about a new song starting near the Cook Islands and later replacing older songs thousands of miles away. Therefore, Choice B is the correct answer.