True, with all the plants and different sediments it sorta acts as a natural filter of pollution, oh and yes organisms are greatly abundant in wetlands and diverse.
The wetland is considered as natural water filters because they clean up the fertilizers and pesticides from the agricultural run off, waste from the industries like mercury can also be treated with the help of wetlands.It has variety of plants and animals present in it to clean the pollution.
The other types of pollution from industries and other sources can also be treated by wetlands. Without wetlands, the government will need to invest more on cleaning of the water bodies.
So, it is true that wetlands are important as they serve as natural filters for pollution.
Option - IT IS BASED ON PREDICTION because they have not had any way of telling where or when it has happened or occurred so you must predict how it happens or works.
