Based on the excerpt, one can draw a conclusion about sea walls that, 'If they are not well planned, they can damage places with sea life.'
Answer: Option D.
Explanation:
The above mentioned excerpt provides a description of an increase in sea level and its preventive measures. From the last two lines of the excerpt we can conclude that, in order to protect the shores from erosion, sea walls or any other related structures can be build. But sea walls should be well planned because failure to do so can damage the sea life which is the habitat for many plants and animals.
