Listen to part of a lecture in an environmental science class. The professor is discussing the role of wetlands in flood control.
Professor: Today, we're going to talk about wetlands and their often-overlooked role in flood mitigation. When people think of flood prevention, they usually picture dams or levees. However, natural wetlands act as giant sponges. They absorb excess rainwater and slowly release it over time, which reduces the peak flow of rivers during storms. This process is particularly effective in coastal areas, where wetlands can buffer storm surges. Moreover, wetlands filter pollutants, improving water quality. But here's the problem: over the past century, about 60% of the world's wetlands have been drained for agriculture or urban development. This loss has made many regions more vulnerable to flooding. For instance, the devastating floods in the Mississippi River basin in 1993 were partly attributed to the loss of upstream wetlands. So, restoring and protecting wetlands is not just an environmental issue; it's a critical strategy for disaster risk reduction.
❓ 题目 What is the professor's main point about wetlands?
A. A) Wetlands are less effective than dams in flood control.
B. B) Wetlands only help filter pollutants, not control floods.
C. C) Wetlands significantly reduce flood risk and should be preserved.
D. D) The loss of wetlands has no impact on flooding.
✅ 正确答案
C) Wetlands significantly reduce flood risk and should be preserved.
