Today in our environmental science lecture, we're discussing urban green spaces. A recent study in Melbourne found that parks can reduce local temperatures by up to 4 degrees Celsius during heatwaves. However, the cooling effect depends on tree canopy coverage. Areas with less than 30% canopy showed minimal temperature differences. Interestingly, the study also noted that residents living within 500 meters of a large park reported better mental health, but only if the park had maintained walking paths. Without these paths, usage dropped significantly, especially among elderly people.
❓ 根据讲座内容，公园要产生显著的降温效果，需要具备什么条件？
A. A. 公园的直径必须大于500米。
B. B. 公园的树冠覆盖率必须至少达到30%。
C. C. 公园必须包含维护良好的步行路径。
D. D. 公园必须位于住宅区内。
✅ 正确答案
B. The park must have at least 30% tree canopy coverage.