Answer:It summarises the main points and leaves a thoughtful end
Step-by-step explanation:
By reading this text above one can have an idea of what the essay was about because the main points are summarized clearly and precisely.
You have an idea what the issue is which is discussed in the essay and this place an emphasy to the main points which were discussed in the essay.
A thoughtful end is given by the last statement which says this issue of pollution needs to be resolved in the future , it leaves the reader thinking what is it that needs to be done to achieve that goal and is this goal achievable?