Listen to part of a lecture in an environmental science class. Professor: Today we're discussing a fascinating example of ecological adaptation: the saguaro cactus. Found primarily in the Sonoran Desert, this cactus can live over 150 years and grow to be 40 feet tall. What's remarkable is how it has evolved to survive extreme conditions. Its pleated, accordion-like skin allows it to expand and store water during rare rainfalls, sometimes absorbing up to 200 gallons in a single storm. The shallow root system spreads out widely, just a few inches below the surface, to capture moisture quickly. But water conservation is only part of the story. The saguaro's white flowers open at night, when temperatures drop and pollinators like bats are active. These flowers also have a waxy coating to prevent water loss. Interestingly, the cactus provides shelter for many desert animals, such as woodpeckers, which bore holes in its trunk. In return, these birds help disperse seeds. So, the saguaro is not just a survivor; it's a keystone species in its ecosystem.
❓ Pregunta According to the professor, what is one reason the saguaro cactus opens its flowers at night?
A. To absorb moisture from the cooler air
B. To attract nocturnal pollinators like bats
C. To protect the flowers from strong winds
D. To avoid damaging the waxy coating
✅ Respuesta correcta
To attract nocturnal pollinators like bats
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