Viết tích hợp TOEFL

📖 Đoạn văn

The extinction of the dinosaurs at the end of the Cretaceous period has long been attributed to a massive asteroid impact. However, a growing body of evidence suggests that intense volcanic activity, specifically the Deccan Traps eruptions in modern-day India, was the primary driver. First, the timing of the Deccan Traps eruptions coincides precisely with the extinction event, with the most intense phase of volcanism occurring just 250,000 years before the boundary. This temporal correlation is too strong to be coincidental. Second, volcanic emissions of sulfur dioxide and carbon dioxide would have caused severe climate disruption, including rapid global cooling followed by prolonged warming, which could have stressed ecosystems worldwide. Third, the fossil record shows a gradual decline in dinosaur diversity over the last few million years of the Cretaceous, consistent with the long-term environmental stress from volcanism, rather than a sudden catastrophic impact. These points challenge the asteroid impact theory and suggest that volcanic activity was the more plausible cause.

🎧 Bài giảng

The reading argues that volcanic activity caused dinosaur extinction, but this view is flawed. First, while the Deccan Traps eruptions overlapped with the extinction, their most intense phase occurred about 250,000 years before the boundary, and later eruptions were smaller. In contrast, the Chicxulub asteroid impact happened exactly at the boundary, matching the extinction precisely. Second, the climate effects of volcanism were likely less severe than proposed. Sulfur aerosols from volcanoes do cause cooling, but the Deccan Traps released sulfur over hundreds of thousands of years, allowing the climate to adjust gradually. The asteroid impact, however, injected dust and sulfur into the atmosphere in a single pulse, causing a sudden 'impact winter' that would have shut down photosynthesis. Third, the claim of gradual dinosaur decline is not supported by recent studies. High-resolution fossil data show that dinosaur diversity remained stable until the very end of the Cretaceous, just before the impact. The apparent decline in older records is likely due to sampling biases or incomplete fossil preservation. Thus, the asteroid impact remains the most compelling explanation.