Answer:
The statement that best describes how the structure enhances a reader's understanding of this passage is C. It traces the effect of cutting down trees over time.
Step-by-step explanation:
The structure of a piece of writing is essential to organize the ideas in a way the reader is capable of understanding them properly. Ensuring that related sections of your writing are linked and that arguments and information follow an orderly an logical progress are key elements to enhance the readers' comprehension. In this case, the author traced the effect of cutting down trees over time to achieve this goal, so one may say he used the chronological structure.