Answer:
To make the essay more convincing and important.
Step-by-step explanation:
Using specific details in an essay is important. Specific details or supporting evidence makes an essay more intriguing and convincing. It keeps the readers to keep on reading as an essay with specific details does not speak in air.
When a writer uses supporting evidence in the essay, the readers are able to know the facts also. Essays that are not supported by the evidences are usually unconvincing and boring and vague.
In the given passage, the writer has made the use of specific details to make the readers aware of the exactness and the facts about the Great Barrier reef. These supporting details will enable the readers convinced about the essay and will know the importance of it.