❓ 문제 According to the passage, what is one piece of evidence supporting the restorative effects of nature on mental health?
- A. A. Reduced activity in the prefrontal cortex after a nature walk.
- B. B. Increased stress levels in urban environments.
- C. C. The popularity of E.O. Wilson's biophilia hypothesis.
- D. D. The presence of green spaces in all modern cities.