Narrator: Listen to part of a lecture in an environmental science class. Professor: Today we're going to discuss a surprising factor in climate change mitigation: the role of large herbivores, like elephants and bison. You might think that these animals, by consuming plants, would reduce the amount of carbon stored in vegetation. However, recent research suggests the opposite. In grasslands, for example, bison trample the soil, which helps compact it and reduces the release of carbon from the soil. They also selectively eat certain grasses, which allows other carbon-sequestering plants to thrive. In forests, elephants create gaps by knocking down trees, which encourages new growth and increases overall biodiversity. This biodiversity, in turn, can enhance carbon storage. So, while the direct effect of herbivores on plant biomass is negative, the indirect effects on soil and plant diversity can be positive for carbon capture. This is a complex interplay that challenges our simple assumptions about ecosystems. Does anyone have a question?
❓ Pregunta What is the main point the professor makes about large herbivores?
A. They always reduce carbon storage by consuming plants.
B. They can have a positive indirect effect on carbon capture.
C. Their impact on soil is negligible compared to plants.
D. They are the primary cause of climate change.
✅ Respuesta correcta
They can have a positive indirect effect on carbon capture.
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