Why are wetlands important to the health of the overall environment? a. they reduce the levels of erosion by trapping sediment. b. they support a wide variety of organisms. c. they are a medium for the filtration and cleansing of water. d. all of the above are true.

D) All of the above are true.

Explanation:

Wetlands are the regions of land which are covered by water. The water can be fresh water, Saltish water or between these two. Low-lying areas of rivers or oceans, ponds, lakes and marshes, all fall under wetlands.

Wetlands are extremely important for the life on earth because of immense number of services they provide to humans, wildlife and fish. They are more productive region than coral reefs and rain forests.They have an important role in protecting the shores  from the strong action of waves that can cause floods. They also help in trapping sediments and thus lowering the losses due to soil erosion. This makes option A true.They provide habitat and food source to wide array of organisms such as fish and wildlife therefore option B is also true.They also help in the controlling of pollution  because they clean or filter sediment from runoff water which ultimately helps in preventing mud clogging in water reservoirs such as lakes. Therefore, they have a cleansing or filtration action and this makes option C true.

Hence, D is the best option.

Hope it helps!