Narrator: Listen to part of a lecture in a biology class. Professor: Today we're going to talk about a fascinating adaptation in certain deep-sea fish: bioluminescence. Now, many of you know that bioluminescence is the production and emission of light by living organisms. But in the deep ocean, where sunlight doesn't penetrate, this ability is not just for show. It serves critical survival functions. For example, some species use counter-illumination. They produce light on their ventral side, or their belly, to match the faint light coming from above. This makes them invisible to predators swimming below, because their silhouette blends with the background. Another use is for communication. Some fish have light organs that flash in specific patterns to attract mates, much like a visual language. And then there's the classic lure, like the anglerfish, which uses a glowing appendage to attract prey right to its mouth. So, bioluminescence isn't just a pretty light show—it's a suite of evolutionary tools for survival in a dark world.
❓ 質問 What is the main purpose of counter-illumination in deep-sea fish, according to the professor?
A. To attract mates with specific light patterns
B. To lure prey close to their mouths
C. To hide from predators by blending with the light from above
D. To communicate with other fish in the dark
✅ 正解
To hide from predators by blending with the light from above
TOEFL Listening Tips
Skim the questions first to predict the content
Watch for signal words in lectures and conversations (however, actually, in fact)
For main idea questions, focus on the beginning; for detail questions, focus on examples and data
For attitude questions, pay attention to the speaker's tone and word choice
Take notes on keywords; don't try to write down every word
