SAT OwlQuestion bank / Central Ideas and Details
Elephants produce deep rumbles, many of them too low for humans to hear. These sounds travel not only through the air but also through the ground as vibrations. Biologist Amara Ndlovu used buried devices to play recorded alarm rumbles as vibrations in the soil near elephant herds, without sending any sound through the air. The elephants bunched together and turned toward the source, just as they do when they hear alarm calls. Ndlovu concluded that elephants can sense and interpret messages carried through the ground, likely through sensitive nerve endings in their feet and trunks.
Which choice best states the main idea of the text?
Elephants produce alarm rumbles more often than any other type of call.
Ndlovu found that elephants cannot hear low-frequency sounds through the air.
Elephants bunch together whenever they detect any vibration in the ground.
Ndlovu's experiment suggests that elephants can detect and respond to messages carried through the ground.
Show answer and explanation
Answer: D
The text describes Ndlovu's experiment: alarm rumbles sent only through the soil made elephants react as they do to alarm calls. Her conclusion is that elephants can sense and interpret ground-borne messages. Choice D states this main idea.
Choice C overgeneralizes: the elephants reacted to recorded alarm rumbles, and the text says nothing about how they respond to any vibration at all.
Why the other choices are wrong
- A. The text does not compare the frequency of alarm rumbles to other calls. It focuses on how elephants detect ground vibrations, not how often they produce specific sounds.
- B. The passage states that elephants react to vibrations sent through the soil, not that they are unable to hear low-frequency sounds traveling through the air.
- C. The text only describes a reaction to recorded alarm rumbles. It does not support the claim that elephants bunch together in response to any ground vibration.
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